1 . Benign tumors
2. Malignant tumors
Benign rectal tumors
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The most frequent are polyps.
Polyp is a localised elevated lesion arising from an epithelial surface.
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Polyp - adenoma : 90%- other ( inflammatory, hyperplastic etc. ) : 10%
2 types of adenoma : tubular ( pedunculated ) 20%
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villous ( sessile ) 80%
Neoplastic Polyps
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? These lesions are dysplastic? The risk of malignant degeneration is related to both the size
and type of polyp.
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? Tubular adenomas are associated with malignancy in only 5% ofcases
? Villous adenomas may harbor cancer in up to 40%
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? Tubulovillous adenomas are at intermediate risk (22%)? Invasive carcinomas are rare in polyps smaller than 1 cm
? Polyps may be pedunculated or sessile
? Pedunculated polyps : Colonoscopic snare excision
? Sessile polyp: Transanal operative excision
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? The site of sessile polypectomies should be marked byinjection of methylene blue or India ink to:
? guide follow-up colonoscopy sessions
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? ensure that the polyp has been completely removed? facilitate identification of the involved bowel segment should
operative resection be necessary
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? Colectomy is reserved for? large, flat lesions
? focus of invasive cancer is confirmed in the specimen.
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? These patients may be ideal candidates for laparoscopiccolectomy
Hamartomatous Polyps (Juvenile Polyps)
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? Not usually premalignant
? These lesions are the characteristic polyps of childhood
but may occur at any age.
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? Bleeding is a common symptom and intussusception
and/or obstruction may occur.
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? Because the gross appearance of these polyps isidentical to adenomatous polyps, these lesions should
also be treated by polypectomy.
? Familial juvenile polyposis
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? Autosomal dominant disorder
? Annual screening :between the ages of 10 and 12 years.
Treatment is surgical and depends in part upon the degree of
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rectal involvement.? If the rectum is relatively spared, a total abdominal colectomy
with ileorectal anastomosis may be performed
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? If the rectum is carpeted with polyps, total proctocolectomy is the
more appropriate operation
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Peutz-Jeghers syndrome? polyposis of the smal intestine, and lesser extent, polyposis of the colon
and rectum.
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? Characteristic melanin spots are often noted on the buccal mucosa andlips of these patients.
? Not at significant risk for malignant degeneration.
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? Carcinoma may occasional y develop.? Because the entire length of the gastrointestinal tract may be affected,
surgery is reserved for symptoms such as obstruction or bleeding or in
whom polyps develop adenomatous features.
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? Screening consists of a baseline colonoscopy and upper endoscopy at
age 20 years, followed by annual flexible sigmoidoscopy thereafter.
Cronkite-Canada syndrome
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? Gastrointestinal polyposis in association with alopecia, cutaneous
pigmentation, and atrophy of the fingernails and toenails.
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? Diarrhea is a prominent symptom, and vomiting, malabsorption, andprotein-losing enteropathy may occur
? Surgery is reserved for complications such as obstruction
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Cowden's syndrome
Autosomal dominant disorder
hamartomas of all three embryonal cell layers
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Facial trichilemmomas, breast cancer, thyroid disease, andgastrointestinal polyps are typical of the syndrome.
Treatment is otherwise based upon symptoms
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Inflammatory Polyps (Pseudopolyps)
? Not premalignant
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? Microscopic examination shows islands of normal,regenerating mucosa (the polyp) surrounded by areas of
mucosal loss.
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? Polyposis may be extensive, especially in patients with severe
colitis, and may mimic familial adenomatous polyposis.
Familial Adenomatous Polyposis
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? Autosomal dominant condition
? 1% of al colorectal adenocarcinomas.
? The genetic abnormality in FAP is a mutation in the APC gene, located
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on chromosome 5q.? most patients with FAP wil have a known family history of the disease,
up to 25% present without other affected family members.
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? Clinical y, patients develop hundreds to thousands of adenomatous
polyps shortly after puberty.
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? The lifetime risk of colorectal cancer in FAP patients approaches 100%by age 50 years.
? Flexible sigmoidoscopy of first-degree relatives of FAP patients
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beginning at age 10 to 15 years
? APC gene testing may be used to screen family members
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? Positive: annual flexible sigmoidoscopy beginning at age 10 to15 years
? Negative: screening starting at age 50 years
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? FAP patients are also at risk for the development of adenomas
anywhere in the gastrointestinal tract, particularly in the duodenum.
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? Periampul ary carcinoma is a particular concern.? Upper endoscopy is therefore recommended for surveil ance every
1 to 3 years beginning at age 25 to 30 years
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? Treatment is surgical? Three operative procedures can be considered
? total proctocolectomy with either an end (Brooke's)
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ileostomy or continent (Kock's) ileostomy? total abdominal colectomy with ileorectal anastomosis
? restorative proctocolectomy with ileal pouch?anal
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anastomosis with or without a temporary ileostomy
Hereditary Nonpolyposis Colon Cancer
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(Lynch's Syndrome)? more common than FAP
? extremely rare (1 to 3%)
? The genetic defects associated with HNPCC arise from errors in
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mismatch repair and study of this syndrome has elucidated many
of the details of the RER pathway.
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? an autosomal dominant pattern? development of colorectal carcinoma at an early age
? The risk of synchronous or metachronous colorectal carcinoma is
40%. HNPCC may also be associated with extracolonic
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malignancies, including endometrial, ovarian, pancreas, stomach,
small bowel, biliary, and urinary tract carcinomas.
? Screening colonoscopy: recommended annual y for at-risk patients
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beginning at either age 20 to 25 years or 10 years younger than the
youngest age at diagnosis in the family, whichever comes first.
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? Because there is a 40% risk of developing a second colon cancer,total colectomy with ileorectal anastomosis is recommended once
adenomas or a colon carcinoma is diagnosed, or if prophylactic
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colectomy is decided upon.
? Annual proctoscopy is necessary because the risk of developing
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rectal cancer remains high.? Similarly, prophylactic hysterectomy and bilateral salpingo-
oophorectomy should be considered in women who have
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completed childbearing.
Familial Colorectal Cancer
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? Nonsyndromic familial colorectal cancer accounts for 10to 15% of patients with colorectal cancer.
? Screening colonoscopy is recommended every 5 years
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beginning at age 40 years or beginning 10 years before
the age of the earliest diagnosed patient in the pedigree.
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? No specific genetic abnormalities are associated withfamilial colorectal cancer, the defects found in either the
LOH pathway or RER pathway may be present in these
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patients.
Adenoma Carcinoma sequence
Rectal carcinoma
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Factors associated with Factors associated withincreased risk for CRC
decreased risk for CRC
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? Lack of physical activity ? MVI containing folic acid
? Consumption of red meat ? ASA and other NSAID's
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? Obesity? Post menopausal HRT
? Cigarette smoking
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? Ca supplementation
? Alcohol use
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? Selenium? Consumption of fruits,
vegetables and fiber
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? Rectal cancer ( adenocarcinoma ) arising from the epithelial cellsof the rectal mucosa.
? 50% of all colorectal tumors are located in the rectum
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? The incidence rate rises dramatically during the fifth decade of life
? Increased risk of colorectal cancer associated with cigarette
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smoking is dependent on the molecular characteristics of thetumor as defined by APC mutation and hMLH1 expression status
Clinical Presentation
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? Rectal bleeding? Changes in bowel habits
? Increased frequency of defecation, decreased caliber of the
stools, mucus with stools, or mucous diarrhea
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? Sense of fullness,tenesmus,increased straining during defecation.
? Sacral or deep pelvic pain
? Anal pain (occurs when low rectal cancer invades the anal canal)
? Incontinence supervenes when the anal sphincter is involved
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? Liver is the most frequent site of metastasis, followed by the
lung, retroperitoneum, ovary, peritoneal cavity, and rarely the
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adrenal glandsPhysical examination
Digital rectal examination
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? Feel for a mass, assess its location and mobility? Depth of invasion and whether the tumor is tethered or fixed
? Pelvic examination in women
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? Prostate assessment in men
A weak or incompetent sphincter may favor a colostomy.
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? Rigid proctosigmoidoscopic examination? If not obstructed, patients with rectal cancer should
have a preoperative double-contrast barium enema
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or preferably a colonoscopy to assess for
synchronous colon cancer (2% to 9%)
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Endorectal ultrasound
? Depth of tumor invasion into the rectal wall
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? Nodal enlargement? Malignant nodes are differentiated from reactive nodes by
being hypoechoic, hypervascular, and irregular
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? CECT scan abdomen &pelvis
? MRI for patients with locally advanced and recurrent rectal
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cancer requiring an exenterative procedure.? Plain chest radiograph
? Laboratory studies
? Carcinoembryonic antigen (CEA) level
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Up to 95% of patients with advanced hepatic metastasis will
have a CEA level above 20 ng/mL.
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Staging
Management
Surgical excision:
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? Surgical resection of affected bowel with clear margins,
along with the adjacent mesentery and at least 12 regional
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nodes? For rectal tumors, total mesorectal excision with a distal
surgical margin of at least 2 cm is recommended
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? For tumors that are located within 6 cm of the anal verge,
or involve the anal sphincter, wide surgical resection with
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abdomino-perineal resection and permanent colostomy isrecommended
? Local excision, for pal iative treatment or simple polyp
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removal
Radiation therapy:
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? Postoperative radiation, with or withoutchemotherapy, significantly reduces local recurrence
rates
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? Common regimen incorporates infusional 5-
fluorouracil (5-FU) as a radiosensitizer to boost the
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efficacy of pelvic radiation? Administered as 45 to 55 Gy over 5 weeks
Systemic Chemotherapy
? 5-FU has been the mainstay of systemic
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chemotherapy for CRC
? Capecitabine was approved in 2001 as first-line
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therapy for metastatic CRC? Irinotecan (Camptosar), Oxaliplatin (Eloxatin),
Bevacizumab, Cetuximab
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Carcinoid Tumors
? 25% of these tumors are found in the rectum.
? Most small rectal carcinoids are benign, and overall survival is
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greater than 80%.
? >60% of tumors greater than 2 cm in diameter are associated
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with distant metastases.? less likely to secrete vasoactive substances than carcinoids in
other locations, and carcinoid syndrome is uncommon in the
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absence of hepatic metastases.
? Small carcinoids can be locally resected, either transanally or
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using transanal endoscopic microsurgery.? Larger tumors or tumors with obvious invasion into the
muscularis require more radical surgery.
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