Download MBBS (Bachelor of Medicine, Bachelor of Surgery) 1st Year, 2nd Year, 3rd Year and Final year Surgery 7 Benign And Malignant Tumors of The Rectum PPT-Powerpoint Presentations and lecture notes
Benign And Malignant
Tumors Of The Rectum
1 . Benign tumors
2. Malignant tumors
Benign rectal tumors
The most frequent are polyps.
Polyp is a localised elevated lesion arising from an epithelial surface.
Polyp - adenoma : 90%
- other ( inflammatory, hyperplastic etc. ) : 10%
2 types of adenoma : tubular ( pedunculated ) 20%
villous ( sessile ) 80%
Neoplastic Polyps
? These lesions are dysplastic
? The risk of malignant degeneration is related to both the size
and type of polyp.
? Tubular adenomas are associated with malignancy in only 5% of
cases
? Villous adenomas may harbor cancer in up to 40%
? 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
? The site of sessile polypectomies should be marked by
injection of methylene blue or India ink to:
? guide follow-up colonoscopy sessions
? ensure that the polyp has been completely removed
? facilitate identification of the involved bowel segment should
operative resection be necessary
? Colectomy is reserved for
? large, flat lesions
? focus of invasive cancer is confirmed in the specimen.
? These patients may be ideal candidates for laparoscopic
colectomy
Hamartomatous Polyps (Juvenile Polyps)
? Not usually premalignant
? These lesions are the characteristic polyps of childhood
but may occur at any age.
? Bleeding is a common symptom and intussusception
and/or obstruction may occur.
? Because the gross appearance of these polyps is
identical to adenomatous polyps, these lesions should
also be treated by polypectomy.
? Familial juvenile polyposis
? Autosomal dominant disorder
? Annual screening :between the ages of 10 and 12 years.
Treatment is surgical and depends in part upon the degree of
rectal involvement.
? If the rectum is relatively spared, a total abdominal colectomy
with ileorectal anastomosis may be performed
? If the rectum is carpeted with polyps, total proctocolectomy is the
more appropriate operation
Peutz-Jeghers syndrome
? polyposis of the smal intestine, and lesser extent, polyposis of the colon
and rectum.
? Characteristic melanin spots are often noted on the buccal mucosa and
lips of these patients.
? Not at significant risk for malignant degeneration.
? 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.
? Screening consists of a baseline colonoscopy and upper endoscopy at
age 20 years, followed by annual flexible sigmoidoscopy thereafter.
Cronkite-Canada syndrome
? Gastrointestinal polyposis in association with alopecia, cutaneous
pigmentation, and atrophy of the fingernails and toenails.
? Diarrhea is a prominent symptom, and vomiting, malabsorption, and
protein-losing enteropathy may occur
? Surgery is reserved for complications such as obstruction
Cowden's syndrome
Autosomal dominant disorder
hamartomas of all three embryonal cell layers
Facial trichilemmomas, breast cancer, thyroid disease, and
gastrointestinal polyps are typical of the syndrome.
Treatment is otherwise based upon symptoms
Inflammatory Polyps (Pseudopolyps)
? Not premalignant
? Microscopic examination shows islands of normal,
regenerating mucosa (the polyp) surrounded by areas of
mucosal loss.
? Polyposis may be extensive, especially in patients with severe
colitis, and may mimic familial adenomatous polyposis.
Familial Adenomatous Polyposis
? Autosomal dominant condition
? 1% of al colorectal adenocarcinomas.
? The genetic abnormality in FAP is a mutation in the APC gene, located
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.
? Clinical y, patients develop hundreds to thousands of adenomatous
polyps shortly after puberty.
? The lifetime risk of colorectal cancer in FAP patients approaches 100%
by age 50 years.
? Flexible sigmoidoscopy of first-degree relatives of FAP patients
beginning at age 10 to 15 years
? APC gene testing may be used to screen family members
? Positive: annual flexible sigmoidoscopy beginning at age 10 to
15 years
? Negative: screening starting at age 50 years
? FAP patients are also at risk for the development of adenomas
anywhere in the gastrointestinal tract, particularly in the duodenum.
? 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
? Treatment is surgical
? Three operative procedures can be considered
? total proctocolectomy with either an end (Brooke's)
ileostomy or continent (Kock's) ileostomy
? total abdominal colectomy with ileorectal anastomosis
? restorative proctocolectomy with ileal pouch?anal
anastomosis with or without a temporary ileostomy
Hereditary Nonpolyposis Colon Cancer
(Lynch's Syndrome)
? more common than FAP
? extremely rare (1 to 3%)
? The genetic defects associated with HNPCC arise from errors in
mismatch repair and study of this syndrome has elucidated many
of the details of the RER pathway.
? 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
malignancies, including endometrial, ovarian, pancreas, stomach,
small bowel, biliary, and urinary tract carcinomas.
? Screening colonoscopy: recommended annual y for at-risk patients
beginning at either age 20 to 25 years or 10 years younger than the
youngest age at diagnosis in the family, whichever comes first.
? 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
colectomy is decided upon.
? Annual proctoscopy is necessary because the risk of developing
rectal cancer remains high.
? Similarly, prophylactic hysterectomy and bilateral salpingo-
oophorectomy should be considered in women who have
completed childbearing.
Familial Colorectal Cancer
? Nonsyndromic familial colorectal cancer accounts for 10
to 15% of patients with colorectal cancer.
? Screening colonoscopy is recommended every 5 years
beginning at age 40 years or beginning 10 years before
the age of the earliest diagnosed patient in the pedigree.
? No specific genetic abnormalities are associated with
familial colorectal cancer, the defects found in either the
LOH pathway or RER pathway may be present in these
patients.
Adenoma Carcinoma sequence
Rectal carcinoma
Factors associated with Factors associated with
increased risk for CRC
decreased risk for CRC
? Lack of physical activity ? MVI containing folic acid
? Consumption of red meat ? ASA and other NSAID's
? Obesity
? Post menopausal HRT
? Cigarette smoking
? Ca supplementation
? Alcohol use
? Selenium
? Consumption of fruits,
vegetables and fiber
? Rectal cancer ( adenocarcinoma ) arising from the epithelial cells
of the rectal mucosa.
? 50% of all colorectal tumors are located in the rectum
? The incidence rate rises dramatically during the fifth decade of life
? Increased risk of colorectal cancer associated with cigarette
smoking is dependent on the molecular characteristics of the
tumor as defined by APC mutation and hMLH1 expression status
Clinical Presentation
? Rectal bleeding
? Changes in bowel habits
? Increased frequency of defecation, decreased caliber of the
stools, mucus with stools, or mucous diarrhea
? 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
? Liver is the most frequent site of metastasis, followed by the
lung, retroperitoneum, ovary, peritoneal cavity, and rarely the
adrenal glands
Physical examination
Digital rectal examination
? Feel for a mass, assess its location and mobility
? Depth of invasion and whether the tumor is tethered or fixed
? Pelvic examination in women
? Prostate assessment in men
A weak or incompetent sphincter may favor a colostomy.
? Rigid proctosigmoidoscopic examination
? If not obstructed, patients with rectal cancer should
have a preoperative double-contrast barium enema
or preferably a colonoscopy to assess for
synchronous colon cancer (2% to 9%)
Endorectal ultrasound
? Depth of tumor invasion into the rectal wall
? Nodal enlargement
? Malignant nodes are differentiated from reactive nodes by
being hypoechoic, hypervascular, and irregular
? CECT scan abdomen &pelvis
? MRI for patients with locally advanced and recurrent rectal
cancer requiring an exenterative procedure.
? Plain chest radiograph
? Laboratory studies
? Carcinoembryonic antigen (CEA) level
Up to 95% of patients with advanced hepatic metastasis will
have a CEA level above 20 ng/mL.
Staging
Management
Surgical excision:
? Surgical resection of affected bowel with clear margins,
along with the adjacent mesentery and at least 12 regional
nodes
? For rectal tumors, total mesorectal excision with a distal
surgical margin of at least 2 cm is recommended
? For tumors that are located within 6 cm of the anal verge,
or involve the anal sphincter, wide surgical resection with
abdomino-perineal resection and permanent colostomy is
recommended
? Local excision, for pal iative treatment or simple polyp
removal
Radiation therapy:
? Postoperative radiation, with or without
chemotherapy, significantly reduces local recurrence
rates
? Common regimen incorporates infusional 5-
fluorouracil (5-FU) as a radiosensitizer to boost the
efficacy of pelvic radiation
? Administered as 45 to 55 Gy over 5 weeks
Systemic Chemotherapy
? 5-FU has been the mainstay of systemic
chemotherapy for CRC
? Capecitabine was approved in 2001 as first-line
therapy for metastatic CRC
? Irinotecan (Camptosar), Oxaliplatin (Eloxatin),
Bevacizumab, Cetuximab
Carcinoid Tumors
? 25% of these tumors are found in the rectum.
? Most small rectal carcinoids are benign, and overall survival is
greater than 80%.
? >60% of tumors greater than 2 cm in diameter are associated
with distant metastases.
? less likely to secrete vasoactive substances than carcinoids in
other locations, and carcinoid syndrome is uncommon in the
absence of hepatic metastases.
? Small carcinoids can be locally resected, either transanally or
using transanal endoscopic microsurgery.
? Larger tumors or tumors with obvious invasion into the
muscularis require more radical surgery.
This post was last modified on 08 April 2022