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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1499_Библиотеки_им_академика_М_И_Перельмана.pdf
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Variants of the adenomatous polyposis syndrome classified as:
Gardener syndrome (APC mutation at the 3' end of exon 15): osteomas, dental anomalies (form/number), epidermal
cysts, desmoid tumors, thyroid neoplasms, CHRPE.
Turcot syndrome: brain tumors (medulloblastoma, glioblastoma).
AFAP (attenuated FAP): lower number and later onset of both the polyps and the resulting cancer, rectum often
spared.
Nonoperative Treatment
Caveat: currently, nonoperative management can only be considered supportive, but not with the intent to replace surgery.
Chemoprevention: role not defined. NSAID-derivatives with inhibition un-selectively for COX-1/COX-2 or selectively for COX-
2 (eg, sulindac, celecoxib): reduction of colonic polyps, but uncertain whether cancer reduced or delayed; no effect on
duodenal adenomas. Potential benefit for desmoid tumors: overall only a supportive but never a definitive treatment for FAP.
Annual colonoscopy and polypectomy (does not replace need for prophylactic surgery).
Depending on tumor stage: adjuvant chemotherapy (colon cancer), chemoradiation (proven rectal cancer): always in
neoadjuvant setting if ileal J-pouch planned to avoid radiating the pouch.
Operative Treatment
INDICATIONS
Asymptomatic affected member of FAP family: plan surgery at age between 15–25 years.
Symptomatic patients (incidental FAP diagnosis): any cancer, advanced adenoma (large size or high-grade
dysplasia), or increasing number of polyps, unless diffuse metastases or prohibitive contraindications. Caveat:
neoadjuvant chemoradiation for all rectal cancers!
OPERATIVE APPROACH
Proctocolectomy with ileal J-pouch anal anastomosis (IPAA): double-stapling technique (routine), or mucosectomy
and handsewn anastomosis (rectal cancer/dysplasia/very distal polyps).
Colectomy and ileorectal anastomosis (IRA): if < 20 rectal polyps, no cancer.
Proctocolectomy and ileostomy: if contraindication for J-pouch.
Outcome
Prophylactic surgery elimination of CRC, elimination of ampullary cancer, but persistent risk for desmoids, small bowel, and
pouch cancer.
Outcome of therapeutic surgery for CRC, ampullary cancer, and thyroid cancer is dependent on tumor stage.
Follow-Up
Continued annual surveillance/screening of residual rectal mucosa and/or pouch.
Frequency of EGD is dependent on upper GI involvement.
Participation in registry for inherited CRC is recommended.
Cross-Reference
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Carcinogenesis (Ch. 3)
Polyps (211.3) (Ch. 4)
Polyposis syndromes (211.3, 235.2) (Ch. 4)
Colorectal cancer—colon cancer (153.X) (Ch. 4)
(Sub-)Total colectomy, ileorectal anastomosis (open) (Ch. 5)
Proctocolectomy, ileal J-pouch anal anastomosis (open) (Ch. 5)
Chemoprevention of colorectal cancer (Ch. 6)
HEREDITARY NONPOLYPOSIS COLON CANCER (HNPCC, 153.8, V84.09)
Overview
HNPCC (Lynch syndrome I/II, syndrome X) is the most common form of inherited colorectal cancer (CRC). Underlying
autosomal dominant mutations in DNA mismatch repair genes: hMLH1 and hMSH2 (90% of the mutations in HNPCC
families), hMSH6 (7–10%), PMS1, and PMS2 (5%).
Caveat: despite "nonpolyposis" label, cancer arises within polyp precursor lesion, but there are not hundreds of polyps.
Epidemiology
Constitutes 3–5% of all CRC. HNPCC: autosomal dominant disorder, penetrance ~80%. Accelerated adenoma-carcinoma
sequence (2–3 years). Lifetime risk of developing colon cancer ~80%, endometrial cancer 40–60%, urinary tract cancer 18–
20%, ovarian cancer 9–12%. Risk of metachronous colorectal cancer 45% (after segmental resection, 10–15% after total
colectomy/ileorectostomy); 70% of colon tumors are proximal to splenic flexures.
Symptoms
Development of colorectal (and associated) cancer at young age. Symptoms often absent, otherwise not principally different
from sporadic CRC.
Differential Diagnosis
Other types of hereditary cancers: FAP, MAP.
Familial CRC without identifiable gene mutation.
Pathology
Macroscopic: limited number of (often flat) polyps, predominantly right-sided (ie, proximal to splenic flexure).
Microscopic: cancers often poorly differentiated adenocarcinoma; medullary growth pattern, signet ring, and mucinous
differentiation.
Microsatellite instability (MSI): 90–95% of HNPCC tumors are MSI+, high frequency of MSI (changes in
two of the five
panels) compared with 15–20% MSI+ in sporadic CRC.
Evaluation
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REQUIRED MINIMAL STANDARD
All Patients
Identification/management of family members at risk: chart documentation that patient was counseled and informed about
this aspect (caveat: litigation!).
Asymptomatic Patient/Family Members with Positive Family History
Family history, genetic counseling/testing (unless already done).
Annual colonoscopy starting age of 25 years (no later than 10–15 years prior to cancer onset in youngest family member).
Women:
annual endometrial aspiration.
Screening for other extracolonic cancers: lack of clear guidelines
according to family patterns. If cancer, high-grade polyps,
or increasing number of polyps surgery.
Patient < 50 Years of Age with CRC
Family history: Amsterdam criteria? In ~50% of proven HNPCC, families do not meet criteria.
Genetic testing: Bethesda criteria?
Identification/management of family members at risk: chart documentation that patient was informed about this aspect
(caveat: litigation!)
Individual workup as for sporadic CRC prior to surgery.
ADDITIONAL TESTS (OPTIONAL)
Same as for CRC.
Classification
Amsterdam II criteria: ~50% of families who meet criteria have HNPCC.
Bethesda criteria MSI+, MSI–.
Lynch I: CRC only.
Lynch II: CRC and extracolonic malignancies.
Muir-Torre syndrome: inherited CRC with sebaceous tumors of the skin.
Syndrome X: familial CRC of undetermined type; strong family history of CRC only (Amsterdam-positive, MSI-
negative, normal MMR genes), more common on the left side, nonmucinous, not multifocal, average age of onset:
50th decade.
Nonoperative Treatment
Chemoprevention: role not defined.
Annual colonoscopy and polypectomy.
Depending on tumor stage: adjuvant chemotherapy (colon), or (neo-)adjuvant chemoradiation (rectum).
Operative Treatment
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INDICATIONS
Any cancer, advanced adenoma (large size or high-grade dysplasia), or increasing number of polyps, unless diffuse
metastases or prohibitive contraindications.
OPERATIVE APPROACH
Subtotal colectomy (therapeutic + prophylactic): recommended for all tumors proximal to sigmoid colon, unless
rejected by patient or patient-specific medical contraindication to extensive colon shortening).
Segmental colorectal resection: therapeutic only (following oncologic principles).
Rectal cancer in HNPCC: low anterior resection (with/without neoadjuvant chemoradiation), prophylactic
proctocolectomy typically not recommended because of its significant functional impact.
Women (particularly if uterine cancer in family, or mutations in hMSH6, or in hMSH2 and hMLH1):
consideration/discussion of hysterectomy/oophorectomy (when childbearing completed, beginning of menopause, or
during any other abdominal surgery).
Outcome
Controversial whether in a stage-by-stage comparison MSI is associated with better outcome and better response to
chemotherapy than sporadic CRC despite poor histopathologic features.
Follow-Up
Continued surveillance/screening for CRC and extracolonic tumors annual complete endoscopy of colorectal mucosa:
colonoscopy (presurgery), flexible sigmoidoscopy (after surgery), endometrial aspiration.
Cross-Reference
Carcinogenesis (Ch. 3)
Polyps (211.3) (Ch. 4)
Polyposis syndromes (211.3, 235.2) (Ch. 4)
Colorectal cancer—colon cancer (153.X) (Ch. 4)
Right hemicolectomy (open) (Ch. 5)
(Sub-)Total colectomy, ileorectal anastomosis (open) (Ch. 5)
Chemoprevention of colorectal cancer (Ch. 6)
Amsterdam II criteria for HNPCC (App. 2)
Bethesda criteria for MSI testing (App. 2)
Tumor staging in TNM system (App. 2)
COLORECTAL CANCER—COLON CANCER (153.X)
Overview
Colorectal cancer (CRC) is the most frequent malignancy in the realm of the colorectal surgery specialty, the third most
frequent cancer overall, and the second leading cause of cancer death. Cancer therefore in the differential diagnosis of
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almost any symptom.
Intrinsic risk factors: family history, polyps, genetic mutations (FAP, HNPCC), IBD (eg, ulcerative colitis), African American
ethnicity.
Extrinsic risk factors: sedentary lifestyle, smoking, radiation colitis, status post ureterosigmoidostomy; diet high in
fat/calories/protein and alcohol, low in fiber (more recently questioned again); lack of vitamin D, sun exposure, calcium,
folate.
Population risk categories (Table 4–3):
Low or average risk (65–75%): asymptomatic—no risk factors, no CRC in any first-degree relatives.
Moderate risk (20–30%): CRC in one first-degree relative aged 55 years, or two first-degree relatives of any
ages (Table 4–4), personal history of curative resection of colorectal malignancy or large polyp (> 1 cm) or multiple
colorectal polyps of any size.
High risk (6–8%): FAP, HNPCC, IBD.
Table 4–3. Comparison of Major Risk Categories.
Sporadic
Colorectal
Cancer
FAP HNPCC IBD
Variants AFAP, Gardner, Turcot Lynch I/II Ulcerative colitis
Crohn disease
Genetics _ + + ?
Autosomal-dominant Autosomal-dominant
Genes Chromosomal
deletions, k-ras,
DCC, p53, APC
APC MSH2, MLH1, PMS1/2,
MSH6
?
Age of onset > 40 years;
average 70–75
years
Polyps start after age 10–20
years, cancer in nearly 100% by
age 40 years; later onset in AFAP
< 50 years Any, often young patients
Number of polyps Variable, < 10 > 100 < 10 Inflammatory
pseudopolyps
Risk 5–6% of
population
100% > 80% Depending on age at
onset, duration of
disease, extent of active
disease
Location Left > right
colon
Any location Right colon > left Active disease
Chemoprevention NSAID? NSAID ? IBD suppression?
Vitamins?
Calcium?
Screening > 50 years; >
45 years in
African-
Americans
> 10–15 years > 25 or 10–15 years
before cancer onset in
youngest family member
7 years post onset,
annually
Genetic counseling Genetic counseling
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Associated risks ? Ampullary cancer, desmoids,
thyroid cancer, other
abnormalities
Endometrial and other
cancers
Extracolonic disease
AFAP, attenuated FAP; FAP, familial polyposis syndromes; HNPCC, hereditary nonpolyposis colon cancer, IBD, inflammatory
bowel disease.
Table 4–4. Impact of Family History on Risk for Colorectal Cancer.
Affected Family Members Estimated Risk Compared to 6–7% Lifetime Risk in General Population
1 FDR with CRC 2–3
x
2 FDR with CRC 3–4x
1 FDR 40 years with CRC 3–4x
1 FDR with adenomatous polyp 2x
1 SDR (grandparents, aunt/uncle) with CRC 1.5x
2 TDR (cousins etc) with CRC 1.5x
CRC, colorectal cancer; FDR, first-degree relative; SDR, second-degree relative; TDR, third-degree relative.
Evolution from normal colon to established cancer: 10 years (average population), 3–5 years (HNPCC). Slow evolution,
carcinogenesis through visible precursor stage (polyp), and ability to completely visualize the colon make CRC theoretically
completely preventable. Screening guidelines established but not even close to full implementation.
Choice of optimal treatment depends on stage and tumor location, complications of disease, presentation (ie, emergency vs
elective), presence of underlying colonic disease, presence of comorbidities. Distinction of colon cancer (eg, sigmoid cancer)
from rectal cancer very important for treatment planning to define the role of (neo-)adjuvant radiation.
Epidemiology
Annual incidence in US: 145,000 new cases of CRC, 55,000 CRC deaths (9–10% of all cancer deaths). Average lifetime risk:
1:18 Americans (5–6%). Peak incidence during 7th decade, but 5% of patients are < 40 years old, 10% < 50 years old. In
90% of patients tumors are sporadic, 10% have positive family history, 1% FAP. CRC is 90% curable if detected early.
Stage at presentation: stage I = 25%, stage II = 30%, stage III = 35%, stage IV = 20%.
Symptoms
Most commonly asymptomatic symptoms are always late signs of the cancer!
Incidental detection during colonoscopy.
Symptoms: bleeding, unexplained anemia, altered bowel habits, constipation, narrowed stools, complete obstruction,
abdominal pain, perforation, abdominal mass, weight loss.
Complications: massive bleeding, large bowel obstruction, perforation, liver failure.
Differential Diagnosis
Symptoms: any other cause for bleeding or obstruction—IBD, particularly Crohn disease, other forms of colitis (ischemic,
infectious including pseudomembranous C difficile colitis, radiation), diverticulitis, IBS.
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Secondary colon involvement from other malignancies: stomach, pancreas, OB/GYN, kidney, lobular invasive breast cancer,
leukemic infiltrates.
Rare tumors: carcinoid, lymphoma, GIST, melanoma.
Premalignant polyps: particularly villous polyps may involve large and circumferential area.
Nonmalignant: endometriosis, prolapse/intussusception, benign tumors (eg, lipoma), pseudoobstruction (Ogilvie syndrome).
Pathology
MACROSCOPIC
Polypoid friable mass vs ulcerating crater with elevated edges, variable size, and involvement of the circumference
(Figures 4–10A and 4–10B). IBD: cancer growth often flat, diffusely growing into wall.
Pattern of metastatic dissemination: lymphovascular lymph nodes, hematogenous portal system liver
metastases
lung metastases.
Figure 4–10A.
Colorectal cancer specimen with additional polyps.
Figure 4–10B.
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Colorectal cancer specimen with circumferential tumor.
MICROSCOPIC
Adenocarcinoma in the overwhelming majority of cases (> 95%). Rare subforms: mucinous or signet ring cell
carcinoma, adenosquamous carcinoma.
Intramucosal carcinoma (T
is
) = carcinoma in situ = high-grade dysplasia: cancer not penetrating through muscularis
mucosa. Invasive cancer: invasion of muscularis propria and beyond.
Negative prognostic growth patterns: lymphovascular invasion, perineural invasion, extranodal tumor deposits.
Minimum of 12–15 lymph nodes necessary for adequate oncologic staging of specimen.
Evaluation
REQUIRED MINIMAL STANDARD
History: bleeding, change in bowel habits, obstructive symptoms, weight loss?
Clinical examination: palpable tumor, abdominal distention, local tenderness or peritoneal signs, organomegaly, digital rectal
exam
palpable tumor, blood on stool, or melena?
Distinction between sigmoid cancer and rectal cancer: 15 cm from anal verge by means of rigid sigmoidoscopy.
Colonoscopy: gold standard to establish diagnosis, full colonic evaluation always needed prior to elective surgery to rule out
synchronous cancer or polyps to determine extent of resection, low threshold for tattooing of tumor site or most
distal/proximal polyp
facilitation of intraoperative localization, particularly for laparoscopic approach.
Abdominal imaging study (sonography, CT scan): evaluation of involvement of liver or urinary system (Figure 4–10C),
evidence for carcinomatosis?
Figure 4–10C.
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Advanced colorectal cancer with liver metastases or hydronephrosis.
Tumor marker: CEA.
Chest x-ray (or chest CT): metastatic disease, free air, cardiopulmonary operability?
ADDITIONAL TESTS (OPTIONAL)
Contrast studies (barium or Gastrografin enema): incomplete colonoscopy, nearly obstructing tumor, suspected perforation (
water-soluble contrast).
Virtual colonoscopy: role not defined, risk of perforation.
MRI, PET, PET-CT: role not yet defined in primary assessment.
Blood work: anemia, liver function (albumin, PTT, PT), kidney function.
Classification
Based on location in colon.
Based on stage: localized, locally advanced (size, infiltration of other structures), metastatic.
Based on TNM stage.
Nonoperative Treatment
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Inoperable patients due to comorbidities.
Inoperable/incurable due to extent of abdominal tumor (eg, carcinomatosis)
symptom control, possible stenting.
Metastatic disease with liver replacement > 50%
palliative chemotherapy.
Operative Treatment
INDICATIONS
Any colon cancer (unless prohibitive contraindications).
Even in presence of systemic tumor manifestations, achieving local tumor control still desirable, potentially
simultaneous or staged metastasectomy in curative intent still possible.
OPERATIVE APPROACH
Curative Intent
Oncologic resection with lymphadenectomy: > 5 cm safety margin, exact extent of resection depends on site of
tumor and lymphovascular drainage (Figure 4–10D):):
– Cecum/ascending: right hemicolectomy with right branch of middle colic artery.
– Hepatic flexure/transverse colon: extended right hemicolectomy including full middle colic artery.
– Splenic flexure: (1) extended left hemicolectomy including middle colic artery, (2) extended right
hemicolectomy/subtotal colectomy.
– Descending colon: (1) left hemicolectomy with left branch of middle colic artery to IMA/left colic artery, (2)
subtotal colectomy.
– Sigmoid colon: sigmoid resection with superior hemorrhoidal artery or IMA.
Special considerations:
– Synchronous cancers: (1) two separate resections, (2) subtotal colectomy.
– Cancers adhering to other structures: en-bloc resection.
– Liver metastases: simultaneous resection reasonable if feasible and tolerated (vs staged resection).
– Prophylactic oophorectomy not indicated but recommended when one or both ovaries grossly abnormal.
– Carcinomatosis: resection of primary tumor, no routine role for intraperitoneal catheter.
– Laparoscopic approach equivalent in skilled hands.
Patient < 50 years/HNPCC: (1) (sub-)total colectomy with ileosigmoidal/-rectal anastomosis, (2) segmental resection
(as above)
FAP: (1) proctocolectomy, (2) total abdominal colectomy with ileorectal anastomosis if no rectal cancer and number
of rectal polyps < 20.
Sentinel lymph node mapping: concerns about high false-negative rate, role not defined.
Figure 4–10D.