GASTROENTEROLOGY LITERATURE REVIEW
August 23, 2001
American Gastroenterological Association. Medical Position Statement: Hereditary Colorectal Cancer and Genetic Testing. Gastroenterology 2001;121:195-213.
1. In hereditary nonpolyposis colorectal cancer syndrome:
a. Cancers arise on flat colonic mucosa, the polyp à cancer sequence is never present.
b. Cancer forms in polyps, but there is no polyposis syndrome
c. Individuals with a HNPCC mutation have a 70% to 80% chance of developing cancer
d. Cancer arises earlier (mean age 44) and preferentially on the right colon
e. Cancer survival after resection is better than for those with sporadic tumors
2. Follow-up of FAP patients after colectomy should include
a. sigmoidoscopy every 6 months if total colectomy not done
b. Upper endoscopy with biopsies of the stomach, small intestine and periampullary
region every 6 months to 4 years depending on polyp burden
c. subtotal thyroidectomy
d. annual exam of the thyroid, consider thyroid ultrasound exams
e. therapy with selective COX-2 inhibitors for those who have undergone total
proctocolectomy
f. Consider endoscopic surveillance of the ileoanal pouch.
3. Characteristics of FAP include
a. 50% will develop adenomas by age 15, 95% by age 35
b. adenomas are predominantly located on the right colon
c. adenomas in extra-colonic sites are extremely rare
d. extra-intestinal malignancies are increased in FAP patients
e. Gardner syndrome refers to an older terminology describing FAP patients with
extraintestinal manifestations
f. Thyroid, biliary tree and pancreatic malignancy are more common in FAP patients
than the general population
4. The mutations that account for the majority of cases of HNPCC syndrome are:
a. APC gene mutations
b. mutations in the 5q21 gene
c. mismatch DNA repair gene mutations
d. hMLH1 and hMSH2 mutations
e. none of the above
5. First degree relatives of patients with FAP should:
a. commit suicide
b. Start screening at age 10-12 with colonoscopy only
c. Start screening at age 10-12 with genetic testing for APC mutation based on the
index case
d. If genetic testing not possible, start screening at age 12 with flexible sigmoidoscopy
yearly, increase interval with each decade.
e. First degree relatives of patients with FAP who have not developed the syndrome by
age 50 can then be screened for colorectal cancer following the usual guidelines.
True or False
6. Among patients with colon cancer, 80% have sporadic cancers, 20% have a potentially definable genetic component.
7. “Attenuated” FAP (<100 polyps) is not associated with mutations in the APC gene
8. Almost all cases of FAP are caused by germ line mutations of the APC gene on chromosome 5q21
9. Once colorectal polyps develop in patients with genetic predisposition for HNPCC syndrome, subtotal colectomy is recommended even if no cancer is found in the polyps.
10. Children of a parent with FAP should be screened with alfa-fetoprotein and liver ultrasound exams up to age 5 looking for hepatoblastoma
11. Ashkenazi Jews who have a first degree relative with colon cancer may benefit from APC gene mutation analysis even if polyposis is not present in the index case.
12. Total colectomy should be postponed until age 25 once the diagnosis of FAP is established.
13. FAP gene testing (APC gene test) is recommended for
a. individuals with >100 adenomas
b. patients with >20 hyperplastic polyps
c. patients with >20 adenomas on a single colonoscopy
d. 1st degree relative of patients with FAP
e. a patient who has had 35 adenomas removed over a 5 year period
14. Extraintestinal malignancies in HNPCC syndrome include
a. endometrial cancer
b. ovarian cancer
c. transitional cell cancer of the ureter and renal pelvis
d. adenocarcinoma of the stomach
e. thyroid malignancy
15. Amsterdam II criteria for the diagnosis of HNPCC syndrome include
a. Histologically confirmed colorectal, endometrial, small bowel, ureter or renal pelvis
malignancy in 3 or more relatives, one of which is a 1st degree relative of the other.
b. Colorectal cancer or breast cancer in 3 or more relatives
c. Colorectal cancer involving at least 2 generations
d. One or more of the cancers diagnosed before age 50
e. Bilateral breast cancer in a first degree relative
f. a, c and d only
16. Microsatellite instability
a. is diagnosed by genetic testing
b. is detected in the normal colonic mucosa of patients with the HNPCC syndrome
c. is responsible for poor cellular telephone reception and static
d. indicates a better prognosis for the colon cancer
e. when found in a colon malignancy, the diagnosis of HNPCC syndrome should be
suspected.
17. Screening of patients at risk for HNPCC syndrome who have not undergone genetic testing include
a. Colonoscopy starting at age 20 to 25 years every 1 to 2 years
b. Yearly colonoscopy starting at age 40
c. Annual screening for endometrial cancer
d. Yearly screening for ovarian cancer in all patients, regardless of family history
e. Annual upper endoscopy with biopsies around the ampulla
f. Recommend hysterectomy and oophorectomy for all affected females