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390 E.G. Weiss and I. Lavery
PET Scans
PET scans are currently approved only for patients with suspected metastatic disease and not for the use in primary staging of colon cancer. However, based on the data from studies
looking at patients with metastatic disease, PET scans may
have a role in determining if any metastatic disease exists at
the time of initial diagnosis.
Appendix: Practice Parameters for the
Detection of Colorectal Neoplasms
Prepared by The Standards Committee, The American
Society of Colon and Rectal Surgeons
Drs. Clifford L. Simmang and Peter Senatore, Project
Directors; Ann Lowry, Chair; Terry Hicks, Council Representative; Marcus Burnstein, Frederick Dentsman, Victor Fazio,
Edward Glennon, Neil Hyman, Bruce Kerner, John Kilkenny,
Richard Moore, Walter Peters, Theodore Ross, Paul Savoca,
Anthony Vernava, W. Douglas Wong
Colorectal cancer is the most preventable visceral cancer,
and its incidence makes it one of the most important. The lifetime probability of an individual developing colorectal cancer
is 5%–6%, translating into an estimated 133,500 new cancers
of the colon and rectum diagnosed annually. It is further estimated that 54,900 people will die of their cancer each year.
Although the incidence was relatively stable during the last
half of the 20th century, there seems to have been a decrease
during the past decade. Mortality is also decreasing, which
suggests greater awareness of the disease and improved detection. Nevertheless, 65% of patients present with advanced disease. It is also reported that when the disease is localized, the
5-year survival rate is approximately 90% for colon cancer and
80% for cancer of the rectum. Most cases are diagnosed after
50 years of age. Although the results of some investigations
have not demonstrated a reduction in mortality with screening,
those statistics do not reflect the number of patients who are
spared from death by early detection and endoscopic removal
of polyps, which blunts the adenoma-to-carcinoma sequence.
A consortium of five medical societies (American College
of Gastroenterology, American Gastroenterological Association, The American Society of Colon and Rectal Surgeons,
American Society for Gastrointestinal Endoscopy, and
Society of American Gastrointestinal Endoscopic Surgeons)
responded to a request for a proposal from the Agency for
Health Care Policy and Research to develop national guidelines for colorectal cancer screening. An interdisciplinary
panel of 16 health care professionals from the fields of medicine, nursing, consumer advocacy, health care economics,
behavioral sciences, and radiology evaluated the currently
available evidence for colorectal cancer screening and made
recommendations for physicians and the public. The panel
studied 3500 peer-reviewed published articles and analyzed
350 articles in detail specifically assessing the following: 1)
performance of screening tests; 2) effectiveness of screening
tests; 3) acceptability to patients; 4) cost effectiveness; and 5)
outcome. A computer simulation of the consequences of conducting the various screening strategies in the population was
done to determine the risks and benefits of each test. The
guidelines made recommendations for people in two groups:
average individuals and individuals at increased risk for
developing colorectal cancer. All screening strategies, including annual fecal occult blood testing, screening sigmoidoscopy every 5 years, screening by both annual fecal occult
blood testing and flexible sigmoidoscopy (every 5 years),
double contrast barium enema every 5–10 years, and
colonoscopy every 10 years were found to have a net benefit.
The panel analyzed an Office of Technology Assessment
study for screening average-risk individuals, which demonstrated that costs associated with colorectal cancer screening
are within the range of cost effectiveness frequently accepted
for other tests, such as mammography.
Recently revised colorectal cancer screening guidelines
from the American Cancer Society have been announced. The
new guidelines divide the population into three categories—
average, moderate, and high risk—with specific recommendations for each. The American Society of Colon and Rectal
Surgeons endorses the colorectal cancer screening guidelines
by the American Cancer Society, which were based in part on
“Colorectal Cancer Screening and Surveillance Clinical
Guidelines and Rationale” published by the consortium and
specialty societies and discussed above. Guidelines governing
the detection of colorectal neoplasms as set forth by The
American Society of Colon and Rectal Surgeons Task Force
are presented in Table 27-1.
Low-Risk Individuals
For low-risk asymptomatic persons, screening should begin at
the age of 50. Low-risk or average-risk patients are those who
are asymptomatic, age 50 or older, have a family history of
colorectal cancer limited to non–first-degree relatives, and no
other risk factors (65%–75% of people). Annual digital rectal
examination should be performed. In addition, fecal occult
blood testing (FOBT) should be performed annually. Yearly
testing is chosen because the randomized trials show that
yearly testing is more effective for decreasing mortality than
testing every 2 years. Rehydration improves the sensitivity of
the test at the expense of specificity. Dietary avoidance of rare
meat, turnips, melons, horseradish, salmon, and sardines can
decrease the rate of false-positive test results. Aspirin and
other nonsteroidal drugs should also be avoided. Diagnostic
workup of positive FOBT results should include an evaluation
of the entire colon. Double-contrast barium enema can examine the entire colon with relatively high sensitivity and specificity for large polyps (>1 cm) and cancers and is less
expensive than colonoscopy. However, it is not possible to
biopsy or remove neoplasms during the same procedure, so
27. Colon Cancer Evaluation and Staging 391
TABLE 27-1. Screening guidelines
Risk Procedure Onset (age, yr) Frequency
I. Low or average: 65%75% Digital rectal exam and one of the 50 Yearly
A. Asymptomatic: no risk factors Fecal occult blood testing and 50 FOBT yearly, flex-sig every 5 yr
B. Colorectal cancer in no Total colon exam (colonoscopy or 50 Every 5–10 yr
first-degree relatives double contrast barium enema
II. Moderate risk: 20%–30%
of people
A. Colorectal cancer in first-degree Colonoscopy 40 or 10 yr before the youngest Every 5 yr
relative, age 55 or younger, or case in the family, whichever is
two or more first-degree relatives earlier
of any age
B. Colorectal cancer in a Colonoscopy 50 or 10 yr before the age of the Every 5–10 yr
first-degree relative older than case, whichever is earlier
age 55
C. Personal history of large (>1 cm) Colonoscopy 1 yr after polypectomy If recurrent polyps, 1 yr
or multiple colorectal polyps If normal, 5 yr
of any size
D. Personal history of colorectal Colonoscopy 1 yr after resection If normal, 3 yr
malignancy, surveillance after If still normal, 5 yr
resection for curative intent If abnormal, as above
III. High risk (6%–8% of people)
A. Family history of hereditary Flexible sigmoidoscopy; consider 12–14 (puberty) Every 1–2 yr
adenomatous polyposis genetic counseling; consider
B. Family history of hereditary Colonoscopy; consider genetic 21–40 Every 2 yr
nonpolyposis colon cancer counseling; consider genetic 40 Every yr
C. Inflammatory bowel disease
1. Left-side colitis Colonoscopy 15th Every 1–2 yr
2. Pancolitis Colonoscopy 8th Every 1–2 yr
FOBT, fecal occult blood testing; Flex-sig, flexible sigmoidoscopy.
following:
flexible sigmoidoscopy
and proctosigmoidoscopy
genetic testing
testing
that patients with abnormalities must undergo an additional
examination by colonoscopy to establish the diagnosis and
provide treatment. Adding flexible sigmoidoscopy to doublecontrast barium enema increases sensitivity, but the magnitude in clinical importance of the additional sensitivity is
uncertain. For these reasons, colonoscopy, which can examine
the entire colon with few false-negative or false-positive findings and can provide definitive treatment of polyps and some
cancers during the same procedure, is usually chosen. For
patients who have negative FOBT results, flexible sigmoidoscopy performed every 5 years is recommended. A 5-year
interval is chosen because of the observation that few polyps
arise and progress to advanced cancer in a 5-year period. If a
polyp is identified, it should be biopsied. If the pathologic
diagnosis is a hyperplastic polyp, then no additional evaluation is required. If the pathologic diagnosis is an adenoma,
then colonoscopy should be recommended.
Colonoscopy permits visualization of the entire colon
directly, along with detection and removal of polyps and
biopsy of cancers throughout the colon. It can be considered
for screening of average-risk individuals. An interval of 10
years has been chosen for asymptomatic, average-risk people
because of strong direct evidence that few clinically important
lesions are missed by this examination and that it takes an
average of approximately 10 years for an adenomatous polyp,
particularly one <1 cm in diameter, to transform into invasive
cancer. In addition, a controlled trial has shown a very low
incidence of advanced adenomas during surveillance followup colonoscopy after an initial examination with negative
20
results.
Indirect evidence from the National Polyp Study
indicates that few polyps will arise and progress to advanced
cancer in less time in patients with no special risk factors.
Moderate-Risk Individuals
Patients at moderate risk for cancer are those who have one or
more first-degree relatives with colorectal cancer or personal
history of colorectal neoplasia (20%–30% of people).
Colorectal Neoplasia in a Close Relative
People with a first-degree relative (sibling, parent, or child)
who has a colorectal cancer or adenomatous polyp should be
offered the same options as average-risk people, but with
392 E.G. Weiss and I. Lavery
several important differences. Those people with two or more
affected close relatives or with an affected close relative
younger than age 55 are at even further increased risk, and
surveillance should begin at the age of 40 years or 10 years
before the youngest case in the family, whichever is earlier.
Colonoscopy is the recommended procedure of choice in this
situation. If colorectal cancer is detected in a close relative
older than age 55, then screening should begin with
colonoscopy at the age of 50 or 10 years before the age of the
case, whichever is earlier.
Patients with Other Risk Factors
Patients with prior endometrial, ovarian, or breast cancer and
those who have had pelvic radiation, could be followed up
according to the guidelines established for patients with a
family history of colon cancer. Patients with a ureterocolonic
anastomosis should be followed up yearly with flexible sigmoidoscopy as a minimum and colonoscopy if the area of
anastomosis cannot be visualized by sigmoidoscopy. Total
colonic examination may be recommended for patients with
acromegaly, Streptococcus bovis, Streptococcus sanguis, or a
Clostridium septicum bacteremia, schistosomiasis, extramammary perianal Paget’s disease, and dermatomyositis.
Polyp Surveillance
in 6–12 months. If these examination results are normal,
colonoscopy should be repeated every 3–5 years as long as
the colon remains clear. If, between total colonoscopic examinations, it is necessary to visualize high-risk sites, such as
those from which a large, sessile polyp has been removed
from the rectum in a piecemeal manner, sigmoidoscopy is a
viable alternative.
Personal History of Colorectal Malignancy
When the colon has been cleared by barium enema or
colonoscopy before resection for cancer, colonoscopy or barium enema is performed again approximately 1–3 years after
surgical resection. If the colon was not cleared before surgical resection, colonoscopy or barium enema is recommended
in 3–6 months. If the follow-up examination results are normal, it is repeated in 3 years and if they are still normal, the
interval between colonic surveillance can be extended to
every 5 years.
High-risk Individuals
Patients at high risk for developing colorectal cancer are those
with a hereditary or genetic predisposition for development of
colorectal cancer, and those patients with inflammatory bowel
disease (6%–8% of people).
For patients who have had a neoplasm identified by sigmoidoscopic examination, a biopsy should be performed. If the
pathologic finding is an adenoma, then a colonoscopy should
be performed. For a polyp detected during a barium enema
examination, a colonoscopy is the recommended procedure.
Colonoscopy can directly inspect the entire colon for the presence of synchronous lesions and allow the removal of polyps
or biopsy of a larger neoplasm. If a large (>1 cm) polyp is
removed, or if multiple polyps of any size are identified and
removed, colonoscopy should be repeated 1 year later. If a
single, small (<1 cm), tubular adenoma is identified and
removed, colonoscopy should be repeated in 3–5 years. If the
results of this examination are normal, then colonoscopy
should be repeated every 5 years. The finding of an adenoma
at any of the follow-up examinations may prompt yearly
colonoscopy until the colon is again cleared of polyps.
Studies may need to be repeated when the entire colon is not
visualized, when there is poor preparation or spasm, when
polypectomy is deemed incomplete or complications ensue
that require intervention, when there is diagnostic uncertainty,
or when tumor debulking is necessary. If the pathologic diagnosis of the initial polyp is a hyperplastic polyp, no diagnostic studies are required at this time and the patient should
continue appropriate screening evaluation.
If a polypectomy is performed for curative intent of an
invasive cancer, follow-up colonoscopy should be performed
Family History of FAP
FAP is characterized by the development of multiple (more
than 100) adenomatous polyps in the colon and rectum.
Inheritance is by an autosomal dominant manner with high
penetrance.
It is recommended that endoscopic examination of the rectum and sigmoid colon be performed every 12 months beginning at the age of puberty (12–14 years). For those patients
with familial adenomatous polyposis who have undergone a
total abdominal colectomy with an ileorectal anastomosis, it
may be desirable to examine the rectum every 6–12 months.
Definitive data regarding appropriate duration of screening is not available. As a general guideline, intense surveillance could change to routine screening at age 40 in families
with uniformly severe disease. In families with variability in
the severity of polyposis, screening should continue until
age 60, although the interval might be increased to 2 years
after age 40.
People with a family history of FAP should also be considered for genetic counseling and consider genetic testing to see
if they are gene carriers. A negative genetic test result rules
out FAP only if an affected family member has an identified
mutation. Gene carriers or indeterminate cases should be
offered flexible sigmoidoscopy as recommended above. If
polyposis is present, colonoscopy is not a reliable screening
27. Colon Cancer Evaluation and Staging 393
test for malignancy and prophylactic surgery is indicated,
preferably before the patient is 20 years old. If genetic test
results are negative, screening should be the same as for lowrisk individuals.
Family History of HNPCC
HNPCC is an autosomal dominant disease characterized by
early-onset colorectal tumors, primarily in the right colon,
that are frequently associated with other cancers. A common
standard for the diagnosis of HNPCC, referred to as the
Amsterdam criteria, is the existence of three or more relatives
with colorectal cancer, one of whom is a first-degree relative
and involves at least two generations, with one or more cases
diagnosed before the age of 50. The Amsterdam criteria have
been criticized as being too rigid, failing to take into account
small families where a dominant pattern of inheritance may
not be obvious and extracolonic cancers that make up the syndrome of HNPCC. When a strong family history is present,
the possibility of HNPCC must be considered.
People with a family history of colorectal cancer in multiple close relatives and across generations, especially if the
cancers occurred at a young age, should receive genetic counseling and consider genetic testing for HNPCC. When performed, genetic test results are positive in approximately 80%
of these families. It is recommended that individuals considering genetic testing be counseled regarding the unknown
efficacy of measures to reduce risks and associated issues and
that care for individuals with cancer-predisposing mutations
be provided whenever possible within the context of research
protocols designed to evaluate clinical outcomes.
Endoscopic examination should begin between the ages of
20 and 25 years or at least 10 years younger than the family
member who had colorectal cancer. The endoscopic procedure of choice is colonoscopy and this should be performed
every 2 years until the age of 40 years. After the age of 40
years, colonoscopy should be performed annually. Unless
genetic testing results are negative, surveillance should be
performed as long as the patient’s overall medical condition
warrants it. Colonoscopy is selected because the cancers and
precursor adenomatous polyps are both predominantly proximal to the splenic flexure.
Inflammatory Bowel Disease
Ulcerative Colitis
The increased risk of developing colorectal cancer in patients
with inflammatory bowel disease is well established, with a
lifetime incidence of 6% in patients with ulcerative colitis
(UC). Up to 1% of all cases of colorectal cancers seen in the
general population may be associated with inflammatory
bowel disease. The risk of developing colorectal cancer is low
until 8 years of disease duration, after which the risk increases
exponentially to reach as high as 56 times that of the general
population by the fourth decade of disease. The degree of risk
also depends on extent of involvement and age of onset. The
strongest predisposing factor for cancer is the anatomic extent
of the inflammation, with patients at most risk if they have
pancolitis or ulceration extending proximally to the splenic
flexure and least risk if the disease is limited to the rectum and
sigmoid colon. Because the risk of developing dysplasia or
cancer increases with longer disease duration, efficient surveillance calls for more frequent testing as the risk increases
with duration. It is common practice to perform surveillance
colonoscopy every 1–2 years after 8 years of disease in
patients with pancolitis or after 15 years in patients with coli-
6
tis limited to the left colon.
Ulcerative proctitis does not need
extraordinary cancer surveillance.
Crohn’s Disease
Patients with Crohn’s disease have a 20-fold increased risk of
colon carcinoma over the general population; however, less
than the increased risk seen with UC. Compared with sporadic colorectal cancer, colorectal cancers in Crohn’s disease
occur at an earlier age (48 versus 60 years), are more often
located in the right colon, and are more frequently multiple.
In particular, sites of stricture and fistula formation seem particularly prone to the development of carcinomas. It is clear
that Crohn’s disease warrants attention to risk of cancer; however, evidence for the most appropriate surveillance program
is lacking. We recommend a moderate program, such as recommended for left-sided UC with surveillance colonoscopy
every 1–2 years after 15 years of disease.
Reprinted from Dis Colon Rectum 1999;42(9):1123–1129.
Copyright © 2003. All rights reserved. American Society of
Colon and Rectal Surgeons.
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28
Surgical Management of Colon Cancer
Anthony J. Senagore and Robert Fry
All colorectal adenocarcinomas develop from a single transformed cell which through numerous cell divisions unimpeded by cell death forms a macroscopic lesion involving the
lumen of the bowel. The staging of colorectal cancer assesses
the depth of penetration of the bowel wall, the involvement of
regional lymph nodes, the involvement of adjacent organs,
and the presence or absence of distant metastases. An increasingly wide variety of putative molecular markers for aggressiveness and metastatic potential have been analyzed;
however, the most accurate prognostic indicator remains the
true stage of the cancer. This fact is the basis for recognizing
adequate locoregional oncologic principles when performing
curative resections of colon cancer. The purpose of this chapter is to primarily address issues directly related to the safe
and oncologically sound methods of performing a curative
resection of a colonic carcinoma. Important and related
issues, such as clinicopathologic staging systems, the role of
adjuvant or neoadjuvant treatments, and molecular markers
are addressed in detail in other sections of this text.
Preoperative Preparation
Planning an operation for a patient with colon cancer requires
the surgeon to have as much understanding as possible of the
tumor’s location in the bowel, the stage of the cancer, and the
patient’s physiologic status.
A variety of scoring systems are available for grading operative risk of surgical patients. The most widely applied scoring system is the American Society of Anesthesia score (1–4);
however, this tool only provides information regarding the
risk of an anesthesia complication given a certain physiologic
1,2
status.
p-POSSUM which include the additional risks related to
underlying nutritional status and the performance of a colectomy.
individual patient, do provide an estimation of the relative
risks for both the patient and the entire surgical team.
A more recent tool is the POSSUM and the modified
3–5
These tools, although of limited specificity for the
Localization of the tumor and the histopathology are important data elements that allow preoperative selection of an operative plan and selection of the optimal resection margins. The
presence of a lesion at watershed areas of vascular supply such
as the hepatic and splenic flexures may require more extensive
resection of colonic length for a safe and complete oncologic
procedure. An extended right or left colectomy may be indicated
to remove all contributing vascular supplies. In addition, information consistent with the hereditary nonpolyposis colon cancer
(HNPCC) (right-sided lesion, Crohn’s-like inflammatory
response, young patient, and positive family history) would support the resection of the abdominal colon rather than a simple
segmental resection. This diagnosis may also be supported by
special stains of the biopsy specimen which demonstrate
microsatellite instability, the hallmark of the disease which
develops from mutations in the DNA mismatch repair system.
Colonoscopy is widely used today and represents the
optimal means of diagnosing the lesion, identifying location,
providing histopathologic material, and tattooing for intraoperative localization when required. Contrast enema is another
means of localizing the lesion anatomically which should be
considered to localize a lesion when colonoscopy fails to
clearly define the portion of bowel involved. Computed
tomography (CT) allows the localization of larger lesions,
identification of local organ invasion, and provides important
staging information regarding the presence of extracolonic
disease, particularly liver involvement. Although intraoperative ultrasound may provide this information, most surgeons
will obtain a CT as a screening tool (see Practice Parameters).
Although positron emission tomography has recently been
approved for colon cancer staging, in isolation its role in
assessing the majority of primary, curable lesions remains
speculative. It may be very useful for recurrent cancer, where
it is essential to determine the presence of disease outside the
scope of resection and may provide evidence of widely
metastatic disease when planning a radical resection. Thus, an
unnecessary noncurative operation with high morbidity may
be avoided.
395
396 A.J. Senagore and R. Fry
Bowel preparation has historically been considered an
essential component of the preoperative preparation of the
patient with colon cancer. The performance of mechanical
cleansing combined with oral antibiotics reduces the concentration of aerobic and anaerobic bacteria within the colon and
has been shown to decrease the incidence of wound infection
from 35% to 9%.
6–8
However, more recent prospective, randomized studies have questioned the additional benefit of
luminal preparation, compared with the use of appropriate
intravenous antibiotics administered in a timely manner. A
recent metaanalysis by Bucher et al.
9
reviewed 565 patients
with a mechanical bowel preparation versus 579 without a
preparation. Interestingly, all but one study demonstrated a
higher anastomotic leak rate in the mechanical preparation
group with an odds ratio of 1.8.
10,11
Other surgical site infectious complications were also more frequent in the mechanical preparation group. However, most of these studies
included high-volume polyethylene glycol in the preparation
group. Similar conditions may or may not apply to bowel
preparation with the lower volume sodium phosphate
preparation. Selective use of mechanical bowel preparation
in combination with systemic antibiotics may be justified.
A mechanical bowel preparation is still advantageous for
laparoscopic colectomy because the reduction in stool volume within the colon makes manipulation of the bowel easier
with the small instruments and reduces the size of the extraction site.
which should be included with an en bloc resection. It is rare
for cancer of the right colon to be unresectable; however,
extensive involvement of the vena cava, superior mesenteric
artery, or the pancreas may necessitate a palliative resection or
bypass procedure.
The key to an oncologically safe and effective resection of
a colon cancer requires clear lateral margins, resection of the
locoregional lymph node bearing mesentery for both cure and
staging, and fashioning of an accurate and well-vascularized
anastomosis. Therefore, a right colectomy is required for a
tumor at any location in the ascending colon. The author
prefers the medial to lateral “no touch” technique. However,
the section senior editor prefers the lateral to medial technique. Thus, as can be seen, both approaches are acceptable
alternatives.
The Medial Approach
The resection begins with exposure of the right colon mesentery by reflecting the small bowel to the left side of the
abdomen. The right colic artery (present in 50% of cases) and
the ileocolic vessels can be elevated from the retroperitoneum.
A vertical incision is made at the root of the right colon mesentery just caudal to the third portion of the duodenum to the
right of the superior mesenteric artery (see Figure 28-1). The
vessel(s) is elevated off the retroperitoneum and a proximal
ligation is performed at the origin off the superior mesenteric
Surgical Technique
There are many approaches to the technical performance of
each segmental colonic resection. This description will provide general technical methods and document standard
anatomic landmarks that should be common to all patients.
Right Colectomy
The patient is placed supine on the operating table. The modified lithotomy position may be useful in cases in which intraoperative endoscopy is necessary. A vertical midline incision
is made sufficiently long to allow complete visualization of
the operative field. A self-retaining retractor should be placed
so as to allow the entire surgical team free hands to conduct
the procedure. Thorough examination of the abdominal and
pelvic contents should be performed. Particular attention
should be given to potential metastatic sites, especially the
liver. The increasing use of intraoperative ultrasound has
demonstrated the superiority of liver assessment of this
modality compared with clinical examination or CT. In the
female patient, the ovaries should be examined not only for
the risk of metastatic deposits, but also for primary neoplasms. The resectability of the tumor should be assessed with
minimal manipulation of the lesion. It is important to determine the presence of disease adherent to adjacent viscera
FIGURE 28-1. The drawing demonstrates the incision made at the root
of the right colon mesentery just caudal to the third portion of the
duodenum to the right of the superior mesenteric artery.
28. Surgical Management of Colon Cancer 397
artery (see Figure 28-2). The right colon mesentery is then dissected off the retroperitoneum. This will allow identification
of the hepatic branch of the middle colic artery (MCA) as the
transverse colon is approached rostrally. Dissection caudally
toward the terminal ileum permits ligation of the ileal vascular
branches. The right colon can then be released from its peritoneal attachments laterally along the right gutter and transversely over the right iliac artery and brought to the midline.
The hepatic flexure suspensory ligaments should be carefully
divided to avoid injury to the common bile duct and should be
secured with energy or ligatures because of large veins in the
ligament. The terminal ileum should be divided 5–15 cm proximal to the ileocecal valve to ensure good vascular supply (see
Figure 28-3 for extent of resection). The transverse colon is
divided just to the right of the main trunk of the MCA. The
right branch of the MCA may be taken, if required. The
attached omentum over the right side of the transverse colon
should be resected with the specimen. The ileocolic anastomosis can be fashioned according to the desire of the operating surgeon. The author prefers to divide the ileum and colon
with linear staplers and perform a functional end-to-end anastomosis by anastomosing the antimesenteric surfaces of the
bowel segments with a linear cutting stapler and closing the
remaining colotomy with a transverse application of the linear
stapler. Closure of the mesenteric defect is optional but may be
appropriate to prevent trusion of the small intestine around the
terminal ileal vascular pedicle.
FIGURE 28-3. The drawing demonstrates the appropriate levels for
vascular ligation and colonic transition for a right hemicolectomy.
Notably, the transverse colon is divided just to the right of the main
trunk of the MCA, although the right branch of the MCA may be
taken, if required. The middle colic vessels are demonstrated and
may be ligated during the performance of an extended right hemicolectomy. This leaves the descending colon in place supported by
the left colic artery.
FIGURE 28-2. The vessel(s) is elevated off the retroperitoneum and a
proximal ligation is performed at the origin off the superior mesenteric artery. The surgeon’s finger is used to demonstrate the vascular
origin for accurate placement of the ligation.
Lateral Approach
Dissection of the right colon may begin laterally along the
peritoneal reflection fold which attaches colon to retroperitoneum. The avascular plane between mesentery and
retroperitoneum should lead the dissection over the kidney
and duodenum from the lateral aspect to make the right colon
a midline structure. Vascular ligation can be performed as the
final step in the same sites as for the medial approach.
Extended Right Colectomy
An extended right colectomy should be performed for any
lesion involving the transverse colon including the hepatic and
splenic flexure. This procedure requires proximal ligation of the
middle colic vessels which are preserved in a standard right
hemicolectomy (see Figure 28-3). Once again this accomplishes
complete resection, lymph node clearance, and most importantly two well-vascularized bowel segments for anastomosis.
The operation proceeds in similar manner as the right
colectomy described above. However, rather than proceeding
through the transverse colon mesentery to ligate and divide
the right branch of the MCA, dissection continues in the
retroperitoneal plane to identify the main middle colic arterial
trunk anterior to the pancreas. This vessel is ligated and
398 A.J. Senagore and R. Fry
divided. The right colon is then mobilized medially as before
and then the lesser sac is entered through the gastrocolic ligament outside the gastroepiploic artery so that the omentum
can be resected with the transverse colon. The splenic flexure
is released from the tail of the pancreas, tip of the spleen, and
anterior surface of the left kidney. The left colon and mesentery are divided just proximal to the left colic artery which is
preserved for right-sided lesions. The left ascending colic
may be sacrificed for left transverse colon lesions preserving
the left descending and sigmoid vessels, where a more distal
colonic (ileosigmoid) anastomosis is desired. The ileocolic
anastomosis is then constructed based on surgeon preference
with functional end-to-end/side-to-side technique or end-toend technique.
Left Colectomy
The Medial Approach
The small bowel mesentery is mobilized to the right upper
quadrant to expose the origin of the inferior mesenteric artery
(IMA) (Figure 28-4) located just caudal to the third portion of
the duodenum (see Figure 28-4). An incision running along
the base of the left colic and sigmoid mesentery from the
sacral promontory to the ligament of Treitz, exposes the aorta,
bifurcation of the common iliac arteries, and IMA vein. The
IMA is ligated and divided proximal to the origin of the left
colic artery and the inferior mesenteric vein (IMV) is ligated
at the base of the pancreas. The avascular plane filled with
areolar tissue is developed beneath mesentery and left colon
along the entire left gutter. The left ureter is easily identified
at this stage and should be freed from overlying mesentery to
avoid injury before vascular ligation. The mesentery is elevated off the retroperitoneum and the sigmoid colon mobilized from the pelvic ileum. The left colon is finally mobilized
medially from its lateral abdominal wall attachments and the
splenic flexure is released. The attachments to the left kidney,
tail of the pancreas, and tip of the spleen can be released
bloodlessly. Once again, the omentum should be taken with
the left transverse colon. The left MCA in the base of the
transverse colon mesentery is divided to preserve blood flow
to the right transverse colon from the right MCA.
Occasionally, it may be necessary to divide the right MCA to
allow the right transverse colon to reach the sigmoid for an
anastomosis. However, an extended right colectomy and
ileosigmoid or ileorectal anastomosis may be preferable if
there is any concern related to the blood supply of the distal
right colon as the proximal component of the anastomosis.
Another alternative is to perform a retroileal right colon to
rectum anastomosis if maintenance of the right colon is
desired. This is performed by swinging the fully mobilized
colon in a counterclockwise direction down into the pelvis to
place the cut edge of the right colon mesentery across the
pelvic brim (Figure 28-5). Once again the anastomosis is left
to the discretion of the surgeon.
FIGURE 28-4. The small bowel mesentery is mobilized to the right
upper quadrant to expose the origin of the IMA located just caudal
to the third portion of the duodenum (see Figure 28-4). An incision
running along the base of the left colic and sigmoid mesentery from
the sacral promontory to the ligament of Treitz, exposes the aorta,
bifurcation of the common ilial arteries, and IMA vein. The IMA is
ligated and divided proximal to the take-off of the left colic artery.
The left branch of the middle colic vessels will require ligation and
division for a formal left colectomy.
The Lateral Approach
An incision is made first at the attachments of the sigmoid
colon at the pelvic brim and then along the left gutter medial
to the white line of Toldt. An areolar tissue plane is found
between the mesentery of the left colon and retroperitoneal
structures which can be bluntly dissected as far as the midline. The splenic flexure is mobilized with this plane as the
guide. Finally, the medial incision is made along the base of
the left colon mesentery to expose the IMA and IMV as
described above. The procedure proceeds as for the medial
approach.
Sigmoid Colectomy
High ligation of the IMA (Figure 28-4) is necessary when performing a sigmoid colectomy to remove all of the lymphatic
drainage, and more importantly to ensure construction of a
tension-free anastomosis. The ascending branch of the left
colic artery should be preserved to allow retrograde blood flow
via the marginal artery from the middle colic arterial supply.
The splenic flexure should be released to avoid anastomotic
28. Surgical Management of Colon Cancer 399
described above. The terminal ileum should be sufficiently
mobilized to allow easy reach to the rectum. A circular stapled
end-to-end anastomosis or functional end-to-side/side-to-side
anastomosis are both appropriate. Proper sizing of the circular
stapler is needed to avoid ischemia and stricture.
Special Circumstances
Acute Obstruction
Acute colonic obstruction produces dilated bowel with a large
amount of fecal loading proximal to the blockage. The associated bacterial overgrowth coupled with possible impairment of
blood flow in the proximal bowel, have been the primary fac-
FIGURE 28-5. An alternative method of reconstruction that preserves
the right colon is a retroileal right colon to rectum anastomosis. This
is performed by swinging the fully mobilized colon in a counterclockwise direction down into the pelvis to place the cut edge of the
right colon mesentery across the pelvic brim.
tors that have classically dictated resection and proximal diversion. Lee et al.
managed by primary anastomosis and found similar leak rates
(left 6.9% versus right 5.2%) and mortality rates (left 8.9%
versus right 7.3%) when compared with historical nonobstructed controls (<2% and <1%, respectively).
colonic lavage has been advocated as an alternative means of
dealing with the obstructed colon. Several cohort studies have
demonstrated the safety and efficacy of this approach for
avoiding a colostomy without increasing leak rates (<5%) or
14–16
sepsis.
anastomoses has been omental wrapping. A large prospective
randomized trial by Merad et al.
nificant difference in anastomotic leak rates or the sequelae of
those leaks. A complete resection of the tumor and obstructed
proximal bowel with primary ileocolic anastomosis has been
shown to be safe and carry low leak rates.
12
compared left- and right-sided resections
12–16
On-table
Another approach at attempting to protect at-risk
17
did not demonstrate any sig-
18
tension. The sigmoid colon is mobilized to the level of the
middle colic vessels medial to lateral or lateral to medial and
the proximal rectum is mobilized from the sacral promontory.
The patient is always in modified lithotomy position to allow
transanal access for the anastomosis. An end-to-end circular
stapled anastomosis can be performed between proximal left
colon and rectum, after dividing the rectosigmoid junction
with a transverse linear stapler. A leak test with air insufflation
of a submerged anastomotic segment should be performed in
all cases using either an endoscope or bulb syringe.
Total Abdominal Colectomy with Ileorectal
Anastomosis
This procedure may be required for circumstances in which
the patient has been diagnosed with HNPCC, attenuated familial adenomatous polyposis, metachronous cancers in separate
colon segments, and frequently in acute malignant distal colon
obstructions with unknown status of the proximal bowel. The
access to vascular supply and mesenteric dissection has been
Prophylactic Oophorectomy
The debate continues regarding the relative risks and benefits
of a prophylactic bilateral oophorectomy in women with
colon cancer. The potential benefits are removal of an ovary
seeded by colon cancer cells which will manifest as a delayed
metastatic site and reduction in the risk of primary ovarian
cancer in this age group. The data are limited for both issues.
A randomized trial of prophylactic oophorectomy has shown
no benefit to survival.
19
The risk of micrometastatic implants
in the ovary increases with Dukes’ stage and approaches
20,21
10%.
A comparison of cohorts of women with and without prophylactic oophorectomy could not demonstrate a survival advantage but a 3.2% versus 0% risk of primary ovarian
cancer in survivors with ovaries not resected.
22
In general,
prophylactic oophorectomy is not performed.
Colon Cancer and Abdominal Aortic Aneurysm
The simultaneous presence of a colorectal cancer and abdominal aortic aneurysm which requires surgical management
causes a clinical dilemma in many situations. A survey of
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