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RECTAL AND PARARECTAL REGION
131
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R
M
V T
James M.Chur
INTR
ODUCTION
e rectum, which is the organ of defecation, is a unique part of the
gastrointestinal tract. e anatomic and physiologic characteristics
peculiar to this role allow specic and sometimes unique approaches
to management of neoplasms of the rectum. is chapter discusses
options for the management of benign epithelial neoplasms in the
rectum.
RECT
e rectum consists of the lowest 8 inches of the intestinal tract. It is
normally empty and therefore does not constantly engage in peristalsis. When lled with stool by a mass movement, the rectum contracts
to expel the stool. Defecation is accomplished by the reex relaxation
of the internal anal sphincter and the voluntary relaxation of the
external sphincter. Sometimes when defecation is not convenient and
the external sphincter remains closed, the rectum accommodates its
stool, with a temporary reduction in rectal pressure and closure of the
anus. Aer a while, the rectal pressure rises again, although defecation is never as ecient later as it is with the initial urge.
CLINIC
AL ANATOMY AND PHYSIOLOGY
ALLY SIGNIFICANT
ch
ASSOCIATIONS OF RECTAL
FUNCTION
s requirement for the rectum to both accommodate and expel
i
stool is associated with a complete two-layer muscular coat that acts
as a safeguard against polypectomy perforation. It also produces a
mucosa that is more redundant than colonic mucosa and less tightly
attached to the underlying muscularis propria, and thus it is more
pliable and has a greater ability to be pulled into a snare. e lack
of constant peristalsis encourages the development of large sessile
(villous) lesions, and the extraperitoneal position of the lower half
to third of the rectum minimizes the consequences of full-thickness
excision.
doscopic microsurgery (TEM), transanal minimally invasive sur-
en
gery (TAMIS), a Delorme mucosal strip, trans-sacral approaches, and
anterior resection. e advantages and disadvantages of these options
are listed in Table 27-1.
RECT
AL VILLOUS TUMORS
A typical rectal villous adenoma is sessile, large, and so (Fig. 27-1). It
can occur anywhere in the rectum and is sometimes circumferential
or extends for the full length of the rectum. Large villous lesions can
produce a lot of mucus, which is sometimes passed independently
from bowel movements. Large lesions also can cause tenesmus and
bleeding. Smaller lesions can be asymptomatic and may be found on
screening examinations.
ASSESSING
hen a large rectal adenoma is noted, the rst judgment to be made
W
is the likelihood that it is cancerous. Cancer is suggested by hardness,
irregularity, fragility, and xity of the polyp. In large polyps, cancer may occur in one small area while the rest of the polyp remains
benign. However, even a small area of cancer mitigates against some
forms of treatment (e.g., snare polypectomy), whereas others may be
acceptable (e.g., TEM or TAMIS). If cancer is present, it needs to be
staged by rectal magnetic resonance imaging (MRI) or ultrasound, a
chest radiograph, carcinoembryonic antigen, and an abdominal computed tomography (CT) scan. Once a stage is determined, the rectal
cancer is treated according to the clinical situation, which is covered
in Chapter 28. In this chapter we are concerned with the management
of benign lesions.
TMENT
TREA
e desired outcome of treatment is resection without recurrence,
which can be achieved by proctectomy, but which of the less radical
approaches are cost-eective?
THE LESION FOR CANCER
THERAPEUTIC OPTIONS RESUL
TING
FROM THE LOCATION OF THE
RECTUM
everal options are available for obtaining access to lesions of the
S
rectum by virtue of the location of the rectum just above the anus,
in the posterior pelvis. Rectal polyps can be approached transanally,
through operating proctoscopes, or by transabdominal procedures.
Surgeons therefore have the choice of a number of procedures for
dealing with rectal villous tumors: direct transanal excision, endoscopic polypectomy through either exible or rigid scopes, transanal
132
Endoscopic P
Th
e advantages of endoscopic polypectomy are that it is easy to
perform and inexpensive. It can be performed without use of an
anesthetic (except where the tumor approaches the dentate line),
and it has a low complication rate. The disadvantage of snare polypectomy is that piecemeal resection is needed for lesions larger
than 2 cm. However, because of the laxity of the rectal mucosa,
snaring can take place in a submucosal plane, and complete resection is easily achieved (Fig. 27-2). Piecemeal excision may be an
olypectomy
RECTAL AND PARARECTAL REGION
TABLE 27-1: Options for the Removal of Villous Tumors of the Rectum
ocedure Indications Advantages Disadvantages
Pr
doscopic polypectomy Benign tumor
En
Any locations
Can remove large tumors
Low rate of complications
Outpatient
Inexpensive, with no special equip-
ment required
Piecemeal resection is common
High recurrence
133
Transanal excision Low tumor (below the lowest rectal
valve)
Transanal endoscopic
microsurgery
Transanal minimally inva-
sive surgery
Any tumor, including T1, T2 cancer
Any location
Any tumor, including T1, T2 cancer
Any location
Delorme Benign tumor, large and
circumferential
Trans-sacral Benign tumor in mid/upper rectum
No longer used
Anterior resection Very large, circumferential tumors
Suspicious for cancer
Delorme procedure not possible
Complete excision
Low recurrence
Inexpensive
Can be dicult to perform
Stretches the anus
Requires general anesthesia
No special equipment required
Complete excision
Low recurrence
Complete excision
Low recurrence
Costly
Equipment and training needed
Costly
Specialized equipment and train-
ing needed
Low complications
No anastomosis
Dicult to perform
Not possible in all patients
Avoids resection Possible parasacral stula
Complete clearance
Cancer not a concern
No recurrence
Major surgery
Hospitalization
Complications
Altered function
FIGURE 27-1
i
ssue if cancer is present in one of the pieces. The margin status
A typical r
ectal villous adenoma is sessile, large, and soft.
may be impossible to determine, and decisions about the need
for more treatment will depend on the biology of the cancer and
details regarding the patient (e.g., age, gender, and comorbidity),
the cancer (e.g., results of MRI), and the polyp (e.g., its location
in the rectum).
FIGURE 27-2 A postpolypectomy photo.
Transanal Excision
ransanal excision involves direct dissection of a low rectal lesion
T
using conventional open surgery instruments. It is an option for
lesions at or below the inferior rectal valve.
e patient is positioned according to the location of the lesion:
in the Kraske (knee-chest) position for anterior or circumferential
134
lesio
ns and in the lithotomy position for posterior lesions. Use of an
ManageMent
of Rectal Villous
tuMoRs
anal retractor is helpful; options include the Lone Star retractor, a Pratt
bivalve retractor, or an operating proctoscope. Stay sutures allow the
lesion to be pulled down toward the anus. A margin of excision of 1
cm is marked with cautery, and an incision through the rectal wall is
made with coagulation current. e lesion is then resected, usually full
thickness. e specimen is pinned out on a piece of cardboard and oriented for the pathologist. e rectal defect can be closed or le open,
depending on the ease of closure, hemostasis, and the size of the hole.
Transanal excision is oen dicult, especially in patients with a
long, muscular anus. Hemorrhage from a rectal artery can be copious, obscuring the eld and causing issues with excision and repair.
Transanal excision is not to be undertaken lightly.
ransanal Endoscopic Microsurgery/Transanal
T
Minimally Invasive Surgery
TEM a
nd TAMIS, which are minimally invasive techniques, are likely
to be performed much more easily than transanal excision, once use
of the instruments has been mastered. Rectal insuation ensures a
good view. e principles of resection are the same: a 1-cm margin
and a full-thickness excision, with closure of the wound or leaving it
open. ese techniques can be applied to lesions the entire length of
the rectum because a hole in the intraperitoneal rectum can be recognized and repaired. Rectal insuation combined with the natural
elasticity of the rectal wall can enlarge the defect aer removal of even
a small lesion. Such defects can be le open as long as there is no
entry into the peritoneal cavity.
Delorme Pr
e Delorme procedure is used for transanal repair of rectal prolapse.
It consists of a mucosal stripping of the redundant/prolapsing rectum, a plication of the rectal muscular tube, and a reanastomosis of
the mucosa. Its use to resect rectal neoplasms is appropriate only for
benign lesions and only in patients with considerable rectal redundancy or occult intussusception. It is particularly suited to circumferential lesions, for which it is an alternative to anterior resection,
especially in elderly patients who may not tolerate proctectomy clinically or functionally, and whose rectal mucosa may be loose enough
to make a Delorme procedure practical.
ocedure
Anterior Resection
A f
ormal proctectomy is needed for patients with a rectal neoplasm
that is suspicious for cancer, either clinically or by preoperative imaging, or in patients in whom it occupies the majority of the rectal lining. is situation is relatively uncommon. e surgery should be
performed using oncologic principles. A preoperative biopsy is inadequate to exclude cancer in such giant lesions.
FOLLO
W
hen a rectal neoplasm has been removed by local excision, close
surveillance is required. e incidence of recurrence is relatively
high, even when the margins of the initial resection are histologically
clear, which suggests a eld defect where the visible polyp occurs
in a zone of mucosal instability that may continue to produce neoplasms. Follow-up can be performed with exible proctoscopy aer
two enemas (or in the context of a regular colonoscopy), initially at
6 months aer resection and then every 6 months if the patient has
a recurrence, and every year if there is no recurrence. Surveillance
is especially important if severe dysplasia was noted in the original
specimen and if the original polypectomy had been piecemeal.
g g e
u
S
ho SD, Herzig DO, Douthit MA, Deveney KE. Treatment strategies and out-
C
comes for rectal villous adenoma from a single-center experience. Arch
Surg. 2008;143(9):866–870.
Featherstone JM, Grabham JA, Fozard JB. Per-anal excision of large, rectal,
villous adenomas. Dis Colon Rectum. 2004;47(1):86–89.
Keck J O, Schoetz DJ Jr, Roberts PL, etal. Rectal mucosectomy in the treatment
of giant rectal villous tumors. Dis Colon Rectum. 1995;38(3):233–238.
McLemore EC, Coker A, Jacobsen G, etal. eTAMIS: endoscopic visualization
for transanal minimally invasive surgery. Surg Endosc. 2013;27(5):
1842–1845.
Pigot F, Bouchard D, Mortaji M, etal. Local excision of large rectal villous
adenomas: long-term results. Dis Colon Rectum. 2003;46(10):1345–1350.
Tuech JJ, Pessaux P, Regenet N, etal. Endoscopic transanal resection using the
urological resectoscope in the management of patients with rectal villous
adenomas. Int J Colorectal Dis. 2004;19(6):569–573.
S t
W-UP
e d
e
R
a d i n g
rans-sacral Resection
T
e trans-sacral route for excision of a benign rectal neoplasm in the
mid and upper rectum (above the reach of a transanal resection) is
mentioned for historical context. It has been superceded by transanal
minimally invasive techniques.
E
P
P
R C: S
INTR
ODUCTION
Th
e aims of the preoperative evaluation of a patient with rectal
cancer are to assess both the patient and the tumor and offer a
tailored treatment plan that optimizes both cure and sphincter
preservation. Accurate staging of rectal cancer is the foundation upon which the choice of the best therapeutic strategy rests.
Locoregional staging assists in selecting patients who can benefit
from neoadjuvant chemoradiation treatment and in determining
the extent of surgery. Early-stage rectal cancer can be treated by
local excision or radical resection alone, but T3 cancers with a
threatened circumferential resection margin (CRM) may be best
managed by neoadjuvant chemoradiation followed by surgery.
This approach, when combined with skillfully performed surgery,
is associated with the lowest recurrence rates.
In this chapter we discuss our approach to preoperative evaluation of rectal cancer, including clinical assessment, endoscopic
evaluation and biopsy, locoregional staging with endoscopic rectal
ultrasound and/or magnetic resonance imaging (MRI), and investigation for distant metastases with computed tomography (CT) and
other modalities. Finally, we discuss the role and importance of the
multidisciplinary team in preoperative evaluation.
S
Mar
ylise Boutros and Steven D. Wexner
Physical Examination
Precise preoperative assessment of a rectal cancer by the operating
surgeon through use of digital rectal examination and rigid proctosigmoidoscopy is critical. Digital rectal examination should include
assessment of the distance between the lower border of the tumor and
the anorectal ring, its xation to the sphincters and to any adjacent
structures (e.g., vagina, prostate, sacrum), the position of the tumor
(anterior, posterior, or lateral), and the patient’s sphincter tone and
integrity (Table 28-1). Aer this examination, the surgeon can oen
determine whether the patient is a candidate for sphincter-saving
surgery (i.e., low anterior resection or intersphincteric resection with
colorectal or coloanal anastomosis) or will need an abdominoperineal resection.
Abdominal examination should include inspection for prior
incisions and evaluation for abdominal distention when an
obstruction is suspected. Furthermore, for patients in whom a
stoma is anticipated, the right and/or left lower quadrant stoma
site should be marked. Ideally, this marking is performed by enterostomal therapists at a site that will minimize postoperative stoma
complications.
CLINIC
Histor
A det
ailed cancer-specic history is an important initial step to
elicit symptoms that may indicate the location and degree of disease. An asymptomatic patient may have an early, localized tumor,
whereas a change in bowel habits and rectal bleeding may be symptoms of a more advanced tumor. Furthermore, tenesmus, anal pain,
and incontinence are characteristics of an advanced distal lesion
that is impinging on the anal sphincter. Constitutional symptoms
including weight loss, anorexia, and fever may be indicators of systemic disease.
Obtaining a complete family history is important to screen for
hereditary cancer syndromes and at times to refer the patient for
genetic counseling. Any patient with rectal cancer who is younger
than 50 years should be referred, along with patients who have at least
one aected rst-degree relative.
Finally, the history should elucidate prediagnosis bowel habits and
fecal continence, as well as risk factors for postoperative fecal incontinence. Risk factors include previous anorectal surgery or trauma,
vaginal deliveries with or without episiotomies or tears, and relevant
neurologic disorders.
AL ASSESSMENT
y
ENDOSCOPIC EV
ALUATION
AND BIOPSY
A co
mplete colonoscopy should be performed for all patients
who present with a nonobstructing rectal cancer because the
incidence of a synchronous cancer or polyp is 1% to 3% and
20% to 30%, respectively. Patients with partial obstruction as a
result of the rectal tumor may complete colonic evaluation by
CT colonography or double-contrast barium enema. If a patient
does not undergo complete preoperative evaluation of the colon,
a colonoscopy should be performed intraoperatively after gut
lavage or within 6 months of surgical treatment (the second best
option).
All patients should have histologic conrmation of the rectal
cancer before proceeding with a proctectomy. For patients with nondiagnostic biopsies, a repeat biopsy should be performed. Lesions
amenable to local excision may be excised for histologic evaluation,
upon which further treatment decisions will be made. Universal
tumor testing for mismatch repair deciency is oen performed aer
resection, but it is better to perform this testing with a preoperative
biopsy. Screening for microsatellite instability or use of immunohistochemistry to measure the level of expression of mismatch repair
proteins will sometimes suggest Lynch syndrome and trigger genetic
testing. e results also have implications for surveillance and testing
of other organs.
135
136
PreoPera
tive evaluation of the Patient with
rect
cancer:
al
Staging and Strategy
TABLE 28-1: Tumor Characteristics upon Digital
Rectal Examination and Rigid Sigmoidoscopy That
Are Important to Assess and Document Preoperatively
Di
stance from the anorectal ring
Position of the tumor
nterior
A
P
osterior
L
ateral
egree of circumferential involvement
D
Mobility
Mo
bile
ethered
T
ed
Fix
Fixa
tion to the sphincters
Fixation or invasion to adjacent structure
agina/prostate
V
um
Sacr
P
elvic side wall
S
phincter
esting and squeeze tone
R
efect
D
PREOPERA
TIVE STAGING WITH
IMAGING MODALITIES
Locoregional Evaluation
reoperative clinical staging of the depth of tumor invasion (T stag-
P
ing) and the presence of mesorectal lymph node metastases (N staging)
should be performed for all rectal cancers. Other important features
that should be evaluated include CRM and extramural venous invasion
(EMVI). CRM is dened as the shortest distance between the rectal
tumor (including noncontiguous tumor) and the mesorectal fascia in
the total mesorectal excision specimen. A positive CRM is dened as
the presence of tumor 1 mm or less from the resection margin and is
associated with signicantly higher rates of local recurrence. Careful
preoperative assessment of the mesorectal fascia is of prime importance because a potentially threatened CRM is an indication for neoadjuvant treatment. is strategy is used to cause tumor regression away
from the CRM prior to surgery in order to maximize negative CRM.
EMVI refers to extension of the rectal tumor into the vessels beyond
the muscularis propria as visualized on MRI. EMVI has been shown to
be an independent, negative predictor of survival.
High-resolution MRI should be used for local staging of rectal
cancer, whereas endorectal ultrasound (ERUS) may be helpful in distinguishing between benign polyps and early T1 cancers. In dicult
cases, especially those below the mesorectum, obtaining both an MRI
and ERUS sometimes can be useful.
umor Stage and the Circumferential Resection
T
Margin
US provides a complete circumferential image of the rectal wall
ER
using a rigid or exible probe with a water-lled balloon to maintain
acoustic contact. Ultrasound frequency determines the resolution of
Interface with perirectal fat
Mucosa and
muscularis mucosa
Submucosa
T
Muscularis propria
Interface balloon
and mucosa
FIGURE 28-1
ectal ultrasound. (From Edelman BR, Weiser MR. Endorectal ultrasound: its
r
role in the diagnosis and treatment of rectal cancer. Clin Colon Rectal Surg.
2008;21(3):167-177.)
Fiv
e-layer image of the rectal wall obtained by endo
the image. Two-dimensional imaging yields a ve-layer image of the
rectal wall composed of three hyperechoic and two hypoechoic circles
(Fig. 28-1). More recently, three-dimensional ERUS with coronal, sag-
ittal, and transverse images has been used in an attempt to improve
the accuracy of ultrasound imaging. However, ERUS remains an
operator-dependent examination with a considerable learning curve
and interobserver variability. A systematic review that assessed ERUS
accuracy for 4118 rectal cancer cases reported a mean accuracy of 85%
for tumor stage. However, the authors observed that accuracy rates signicantly declined in recent years, which may be attributable to more
recent widespread use of ERUS in low-volume centers compared with
earlier years, along with an inated accuracy in earlier studies.
ERUS may be useful for the assessment of large polyps when a
possibility of invasion exists. ese early cancers involving only the
submucosa can usually be accurately distinguished from those that
penetrate the muscularis propria or extend into the perirectal fat
(Fig. 28-2). ERUS accuracy varies with T stage. Many studies report
better accuracy using ERUS for early compared with advanced rectal
cancers. A review of 31 publications over two decades reported an
overall accuracy of 82% for ERUS, with accuracies ranging from 40%
to 100% for T1 and T2 tumors compared with 25% to 100% for T3
and T4 tumors. In a recent meta-analysis of 11 studies it was found
that the sensitivity of ERUS in identifying T1, T2, T3, and T4 tumors
was 84%, 76%, 96%, and 76%, respectively. ERUS has repeatedly been
reported to overstage T2 lesions. Peritumoral inammation and desmoplastic changes are common causes of this overstaging because
both are dicult to dierentiate from actual tumor borders. Finally,
ERUS cannot be used to evaluate stenotic lesions because the probe
cannot be safely or comfortably inserted into the rectal lumen. Upper
rectal lesions can be dicult to reach with the rigid ultrasound probe
because of the angulation of the sacrum.
Overall, the distance to the CRM is best estimated using MRI.
Although ERUS may be useful in the evaluation of rectal cancers, the
best staging modality is MRI.
MRI of the rectum has been performed with either an endorectal coil or a phased-array surface coil. Although an endorectal coil
provides good resolution of the lesion, it is invasive, uncomfortable,
and cannot be used for stenosing or rectosigmoid lesions. e current standard MRI should be performed using a phased-array coil
and T2-weighted thin sequences perpendicular to the long axis of the
rectum, resulting in high-resolution images with improved spatial
resolution. MRI is less operator dependent than ERUS, yet its interpretation requires standardization and trained radiologic expertise.
Dierentiation of T1 and T2 tumors on MRI can be dicult,
whereas a T3 tumor is more easily identied because it invades the
-
RECTAL AND PARARECTAL REGION
137
A
B
FIGURE 28-2
Irregularity of the middle white ring indicates tumor involvement
confined to the submucosa B, Endorectal ultrasound demonstrating a
T3 lesion. The tumor penetrates the outer black ring of the muscularis
propria into the perirectal fat. (A, From Burdan F, Sudol-Szopinska I, Staro-
wska E, et
sla
diagnosis of r
RE, Weiser MR. Endorectal ultrasound: its role in the diagnosis and treatment
of rectal cancer. Clin Colon Rectal Surg. 2008;21:167-177.)
m
esorectal fat (Fig. 28-3). In a review of 31 publications comparing
ERUS and MRI over two decades, it was found that MRI was more
accurate for advanced disease because it clearly denes the mesorectal fascia, with an overall accuracy for T staging of 76% (T1 and T2
ranging from 29% to 80%, and T3 and T4 ranging from 0% to 100%).
In a recent meta-analysis of 21 studies, MRI could dierentiate T3/T4
from T1/T2 tumors with a sensitivity of 87% (95% condence interval [CI], 81%-92%) and a specicity of 75% (95% CI, 65%-80%).
e mesorectal fascia is best visualized on T2-weighted images
as a hypodense line surrounding the mesorectal fat (see Fig. 28-3).
Using MRI, the majority of patients with a tumor inltrating 5 mm
or more beyond the muscularis propria should be correctly identied. Furthermore, threatened CRM as measured by MRI should
A, Endor
Magnetic resonance imaging and endorectal ultrasound for
al.
ectal lesions. Eur J Med Res. 2015;20:4-14. B, From Edelman
ectal ultrasound demonstrating a T1 lesion.
FIGURE 28-3
rectal cancer with potential circumferential resection margin involvement. T2-weighted axial rectal MRI demonstrating the tumor extending
anterolaterally and lying close to the mesorectal fascia (arrow). (From
ton S, Brown G, Daniels IR, et
Bur
pr
eoperative treatment strategy: the way to eliminate positive circumferential
margins? Br J Cancer. 2006;94:391-397.)
Magnetic r
esonance imaging (MRI) demonstrating T3
MRI directed multidisciplinary team
al.
be accurately detected. In the aforementioned meta-analysis, CRM
involvement was assessed in 986 cases and yielded sensitivity and
specicity summary estimates of 77% (95% CI, 57%-90%) and 94%
(95% CI, 88%-97%), respectively.
us MRI has good accuracy for T stage and CRM assessment.
For upper rectal cancers, dened as cancers 10 to 15 cm from the
anorectal ring, if the CRM is not threatened, MRI may not provide
signicantly more information than CT imaging.
Nodal Staging
Accurate detection of lymph node (N) involvement remains a challenge
for ERUS and MRI, but both modalities are superior to CT imaging. In a
large meta-analysis, the sensitivities and specicities of imaging modalities for nodal staging were as follows: CT (55% and 74%, respectively),
ERUS (67% and 78%, respectively), and MRI (66% and 76%, respectively).
When ERUS is used for N staging, the internal texture rather than
the actual size of a node was found to best correlate with the presence
of metastases. Heterogeneity of the node, hilar reection (internal
echoes near the hilum), and lobulation (the presence of indentations)
are important features of lymph node involvement (Fig. 28-4). ERUS
is not reliable for identication of lymph nodes smaller than 5 mm
in diameter. Overall accuracy of N staging by ERUS is quite variable,
ranging from 58% to 78%, and is less accurate than T staging. In a study
based on histopathologic assessment for 134 patients who had undergone rectal cancer resections without neoadjuvant therapy, the investigators found that the accuracy of ERUS N staging improved for tumors
with increasing T stages. A drawback of ERUS, especially with a rigid
probe, is its limited eld of view. is limitation prohibits detection of
lymph nodes out of the transducer’s range, such as metastases to the
iliac lymph node chain, which are considered M1 disease.
138
characteristics of involved malignant lymph nodes include a
MRI
PreoPera
tive evaluation of the Patient with
mixed signal intensity and an irregular contour (Figs. 28-5, 28-6, and
28-7). ese characteristics are more accurate than size for predict-
ing tumor involvement. MRI cannot detect lymph nodes with tumor
deposits smaller than 2 mm in diameter. A recent meta-analysis of
MRI staging for rectal cancers revealed that the sensitivity and specicity of N staging was 77% and 71%, respectively. In this review, these
summary estimates of sensitivity and specicity were lower than
those for T stage and CRM assessment by MRI, leading the authors to
conclude that MRI is not as reliable for N staging. Nonetheless, MRI
is preferred to ERUS for nodal staging. Continued renement of standardized criteria for lymph node positivity should further improve
MRI accuracy in the future.
rect
cancer:
al
Staging and Strategy
Extramural Venous Invasion
ough not part of TNM staging, EMVI is a histologic feature that
refers to invasion of vessels deep to the muscularis propria. EMVI
appears as a serpiginous extension of the tumor into the mesorectal
fat. Using a classication of EMVI proposed by Brown and colleagues,
EMVI was correctly depicted by MRI with 62% sensitivity and 88%
specicity when compared with nal disease. MRI-EMVI positivity
was signicantly associated with an advanced rectal cancer stage, synchronous distant metastases, and lower survival when compared with
MRI-EMVI–negative tumors. us EMVI has emerged as an important feature to assess on MRI for advanced rectal cancer.
Locoregional Imaging Synoptic Reports
e best staging is undoubtedly achieved when well-trained radiolo-
gists, using the most advanced scanners and protocols, routinely evaluate a high volume of images. Adequate standardized MRI reporting
for rectal cancer is crucial. A cross-sectional observational study of
MRI reporting in Ontario, Canada, showed that only 40% of rectal
cancer MRI reports captured the T stage, N stage, and CRM status.
is nding led to an initiative to develop valid and reliable MRI synoptic report templates to improve consistency of imaging reporting
across the province. e developed MRI synoptic report for rectal
cancer includes a description of (1) overall image quality; (2) tumor
distance from the anal verge; (3) tumor characteristics, including
location and circumferential extent; (4) T category, including invasion of adjacent organs or sphincter involvement; (5) distance to the
mesorectal fascia; (6) EMVI; (7) mesorectal lymph nodes; and (8)
extramesorectal lymph nodes. Use of such standardized MRI reporting is of great value in promoting consistent communication on rectal
cancer cases.
Distant Metastatic Evaluation
reoperative detection of metastases can inuence the manage-
FIGURE 28-4
ectal lymph node with a heterogenous appearance. (From Cârţână ET,
r
Pârvu D, Săftoiu A. Endoscopic ultrasound: current role and future perspectives
in managing rectal cancer patients. J Gastrointestin Liver Dis.
2011;20:407-413. Reprinted with permission.)
Endor
ectal ultrasound demonstrates a metastatic peri
P
-
ment of a patient with rectal cancer. e most common sites of
metastases include the liver, lungs, and peritoneum, and thus
p
reoperative CT scans of the chest, abdomen, and pelvis are used.
Fl
uorodeoxyglucose–positron emission tomography imaging is
AB
FIGURE 28-5 A, Magnetic r
hematoxylin and eosin–stained section of a benign lymph node (arrow).
node status in r
ectal cancer with use of high-spatial-resolution MR imaging with histopathologic comparison. Radiology. 2003;227:371-377.)
esonance imaging demonstrating a benign lymph node with regular borders (arrow). B, Corresponding histopathology
(Fr
om Brown G, Richards CJ, Bourne MW, et
al.
Morphologic predictors of lymph
A B
RECTAL AND PARARECTAL REGION
139
FIGURE 28-6
sponding histopathologic hematoxylin and eosin–stained section shows necrotic tumor in the area corresponding to the low signal intensity on MRI
(arrows).
imaging with histopathologic comparison.
A, Magnetic r
om Brown G, Richards CJ, Bourne MW, et
(Fr
esonance imaging (MRI) scan demonstrating a metastatic lymph node with mixed signal intensity (arrows). B, A corre-
Morphologic predictors of lymph node status in rectal cancer with use of high-spatial-resolution MR
al.
Radiology. 2003;227:371-377.)
A B
FIGURE 28-7
pathologic hematoxylin and eosin–stained section shows irregular borders (arrow).
of l
ymph node status in rectal cancer with use of high-spatial-resolution MR imaging with histopathologic comparison. Radiology. 2003;227:371-377.)
A, Magnetic r
esonance imaging demonstrating a metastatic lymph node with irregular borders (arrow). B, A corresponding histo-
om Brown G, Richards CJ, Bourne MW, et
(Fr
Morphologic predictors
al.
in
dicated to assess equivocal lesions found on routine preoperative
CT scans and for patients with iodine allergies prohibiting a contrastenhanced CT scan. However, the role of routine uorodeoxyglucose–
positron emission tomography in preoperative evaluation of patients
with rectal cancer remains unclear. MRI of the abdomen also may be
used to evaluate uncertain lesions of the liver.
Serum T
S
erum carcinoembryonic antigen (CEA) levels should be measured
umor Markers
preoperatively as a baseline level to which postoperative surveillance levels are compared in order to detect a recurrence. A conrmed elevation in CEA during surveillance should prompt a survey
f
or recurrence. Although an elevated CEA level is not diagnostic or
prognostic, a level greater than 15 mg/mL should raise suspicion for
possible distant metastases.
OLE OF MULTIDISCIPLINARY
R
CANCER CONFERENCES
ultidisciplinary approach for the management of rectal cancer
A m
has become the standard of care. e ideal multidisciplinary team
(MDT) should be composed of specialist surgeons, medical oncologists, radiation oncologists, expert radiologists, expert gastrointestinal pathologists, a genetic counselor, and clinical oncology nurse
specialists. is MDT should meet regularly to discuss all rectal
140
PreoPera
tive evaluation of the Patient with
rect
cancer:
al
Staging and Strategy
ancer cases prior to any treatment decisions and should implement
c
an agreed-upon management plan based on accepted guidelines.
Data from several European countries have demonstrated that
rectal cancer MDTs have been shown to improve decision making,
decrease rates of local recurrence, and improve overall survival. In
the United Kingdom, an audit of positive CRMs (an accepted surrogate measure of the success of rectal cancer treatment) before and
aer the implementation of multidisciplinary rectal cancer conferences was performed. is audit demonstrated positive CRM rates
of 26% and 1% in patients treated before and aer MDT discussion
implementation, respectively. is improvement was due to the introduction of routine preoperative high-resolution MRI and appropriate neoadjuvant treatment recommendations for high-risk tumors.
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patients who were evaluated by an MDT were more likely to receive
appropriate treatment with preoperative radiotherapy. For a subset
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registry demonstrated that preoperative radiologic tumor staging and
discussion at the MDT was associated not only with an increase in
the proportion of patients receiving neoadjuvant treatment but also
with signicantly improved local control and survival. Yet another
United Kingdom–based study demonstrated that adherence to
evidence-based rectal cancer treatment guidelines, including MDT
management, was signicantly associated with improved 5-year survival. More recently, the introduction of MDTs in addition to a total
mesorectal excision education program for surgeons, pathologists,
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treatment on an individual patient basis. e MDT is also one of the
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