Intestinal and Rectal neoplasms Flashcards
Polyps
● Discrete mass lesions that protrude into the intestinal lumen
● Most are asymptomatic, can appear flat, elevated, depressed, pedunculated
● Present in 30% of adult males and 20% females over 50
● Most polyps are small < 5 mm and low risk of becoming malignant
● If larger >1 cm considered advanced, with further dysplastic changes
○ Higher Risk
Four main histologic cell catergories of polyps
- Mucosal adenomatous polyps- 70%
- Mucosal serrated polyps
- Mucosal non-neoplastic polyp
- Submucosal lesions
How polyps lead to carcinoma
● Inactivation of the adenomatous polyposis coli (APC) gene leads to
chromosomal instability- Adenoma type
● KRAS mutation- Serrated type (Kirsten RAt Sarcoma virus)
● BRAF( B-Raf) oncogene activation- Serrated type
How are polyps discovered?
● CT Colonography- potentially 90% of polyps over 1 cm, drops to 50%
sensitivity with smaller polyps, and ↑risk w/ radiation - Bowel prep prior
● Colonoscopy- Considered best test, biopsy obtained, Bowel prep prior
○ Must be done after all positive stool tests, CTs, and flex sigmoidoscopy
Polyp Removal
During Colonoscopy or Flex Sigmoidoscopy
● Biopsy forceps or snare cautery for smaller polyps
● Larger polyps may be removed by snare cautery using a variety of techniques (eg, piecemeal or saline-lift assisted mucosal resection)
● Surgical resection when larger
Complications of polyp removal
● Bowel perforation
● Bleeding
● Residual Cancer
Diagnosis and Surveillance of Tumors of the Small Intestines
EGD, extended duodenoscopy (2 balloon endoscopy), capsule
Symptoms of small intestinal polyps and cancers
● Often asymptomatic
● GI bleeding with hematochezia with acute/ chronic anemia
● Intestinal Obstruction or biliary obstruction
● Neuroendocrine tumor with subsequent symptoms
● Abdominal pain, weight loss, nausea, vomiting,
Hereditary or Polyposis Syndrome
- Examples- FAP (0.5% of CRC) and Lynch Syndrome (3% of CRC)
Suspect with family history or personal history of colorectal cancer that has:
● Affected more than one family member,
● Colorectal cancer developing at an early age (50 years or younger)
● Multiple polyps (more than 10) found on colonoscopy
● Multiple extracolonic malignancies
Familial Adenomatous Polyposis
● Inherited condition characterized by early development of hundreds
to thousands of colonic adenomatous polyps.
● Extracolonic manifestations- Duodenum. Also extraintestinal occur
● Genetic testing confirms mutation of APC gene (90%) or MUTYH gene
(8%).- mutY DNA glycosylase
● Prophylactic colectomy recommended
● Inevitable colorectal cancer (adenocarcinoma)
● Can happen in the absence of genetic mutations
Lynch Syndrome
● Also called Hereditary Nonpolyposis Colon Cancer (HNPCC)
● Inherited condition
● Increases risk of CRC (22-75%), endometrial cancer, ovarian, kidney, bladder, gastric, etc and occurs at younger ages. Screen for those as well
● Unlike FAP, few adenomas, and also rapid progression 1-2 yrs →cancer
● Genetic evaluation of patient and their family members
Options for screening for Colorectal cancer
● Fecal immunochemical test (FIT) annually
● High‐sensitivity, guaiac‐based fecal occult blood test (gFOBT) annually
● Multitarget stool DNA with FIT test every 1-3 years
● Colonoscopy every 10 years
● CT colonography (Virtual Colonoscopy) every 5 years
● Flexible sigmoidoscopy every 5 years (or 10 if used with annual FIT)
Capsule Endoscopy Indications small bowel
○ GI bleeding without identifiable cause
○ Crohns
○ Small bowel tumors
○ Polyps and polyposis syndromes
○ Unexplained diarrhea or abdominal pain
Capsule Endoscopy indications for colon
Colorectal cancer screen or incomplete colonoscopy
US Preventative Task Force -May 2021 (ACS Guidelines same) for Colorectal cancer
● Adults 45 and older regardless of risk factors
○ Stool based or visual exam based on preference
○ Any stool based test that is positive warrants follow-up with colonoscopy
● Continue CRC screen through age 75
● After 76 (Up to 85) depends on life expectancy, patient preference, health
status
● After 85 screening is discouraged
High Risk Individuals for colorectal cancer screening
● Family history of colorectal cancer or polyps
● Family history of a hereditary colorectal cancer syndrome such as familial
adenomatous polyposis (FAP) or hereditary non-polyposis colon cancer
(HNPCC)
● Personal history of colorectal cancer or polyps
● Personal history of chronic inflammatory bowel disease (ulcerative colitis
or Crohn disease)
When to screen high risk individuals for colorectal cancer?
● One first-degree relative diagnosed with colorectal cancer or advanced
adenoma at age 60 years or older start at age 40, prefer q 10 yr colonoscopy● Single first-degree relative diagnosed with colorectal cancer or advanced
adenoma before age 60 years, or those with two first-degree relatives with
colorectal cancer or advanced adenomas.
○ Guideline recommends colonoscopy every 5 years, beginning at age
40 or at 10 years younger than the age at diagnosis of the youngest
affected relative. Note- 8 yrs after Dx of IBD
Colorectal Cancer features
● 2nd leading cause of death from malignancy
● 4.2 % of Americans will develop CRC, mortality rate is decreasing
● Majority are adenocarcinoma
● Personal or family history of adenomatous or serrated polyps or
colorectal cancer are important risk factors.
● Aspirin may reduce risk, but not recommended solely for that
● Diagnosis established with colonoscopy. In US only 67.1% of undergo
screening
Colorectal Cancer S/S
● Early: largely asymptomatic
● Maybe diarrhea from secretory symptoms or obstruction
● Right colon: fecal occult blood
● Left colon: hematochezia, tenesmus, more likely to be obstructive
○ Obstructive symptoms:
■ Change in bowel habits, colicky abdominal pain, constipation, loose
stools
Colorectal Cancer diagnosis
● Rule out CRC in patients over 40 with worrisome change in bowel habits and
symptoms noted on previous slide
● Labs- CBC for anemia, also worrisome are liver changes. Why?
● Carcinoembryonic antigen (CEA)- is prognostic, not used for screening
● Colonoscopy
● Rectal US and MRI can be used to evaluate rectal cancer staging
● CT can be used for distal metastasis
Colorectal Cancer Staging and the 5 year survival rate
Stage 1- 92% for colon, 87% for rectal- may need only surveillance
Stage 2- Node negative, 70-85% for stage IIA, higher rates of recurrence,
consider adjunctive chemotherapy
Stage 3- Node positive, about 30-60% with resection and chemo
Stage 4- Metastatic Disease (20% of patients at initial diagnosis)
● 12 months if non-resectable disease. Chemotherapy
Colorectal Cancer Tx
● Pre and post operative- Chemotherapy and radiation therapy
● Immunotherapy
● Bowel Resection with lymph node biopsy
Ongoing Surveillance Required
● Evaluate q 3–6 months for 2 years, then q 6 months for a total of 5 years
● Laboratory surveillance, serum CEA levels if baseline levels are elevated
● CT chest, abd, pelvis q 6-12 months for 5 years
Anal Cancer
Increased incidence associated with
● Receptive anal intercourse
● Infx with HPV (detected in 80% of anal cancer) - HPV vaccine reduces risk
● Lifetime # of sexual partners
● Anorectal warts
● Cigarette smoking
● Infx with HIV
● Women with anal cancer have higher risk of cervical cancer
Anal Cancer types
● HPV infx assoc. with development premalignant anal
squamous intraepithelial lesions
● Adenocarcinoma (very rare) at anorectal ring
Anal Cancer presentation
● Most common initial symptom: Rectal bleeding
● Anorectal pain
● Sensation of rectal mass
● 20% have no tumor-related symptoms
● If sphincter involved may have leakage from bowel.
● Bleeding from mass at or just above the anal sphincter if attributed to
hemorrhoids may delay dx.
Anal Cancer treatment
● Series of treatments with radiation followed by
chemotherapy. May control without radical surgery
● In past, anus was removed, area closed, bag placed
● Surveillance required
● 5 year survival 80% with localized tumor, and 30% after
metastatic spread (Stage 4)
