2. LYNCH SYNDROME
Named after Dr. Henry Lynch
HNPCC – Hereditary Nonpolyposis Colorectal Cancer
Colorectal, endometrial, ovarian, upper urologic tract,
gastric, small bowel, Biliary/pancreatic, brain
tumors(glioma), sebaceous gland tumors
3. AUTOSOMAL DOMINANT
Germ line mutation in mismatch repair genes
MSH2, MLH1 account for 90% of heterozygous germ
line mutations identified I Lynch Syndrome
MSH6 has the highest risk of endometrial cancer
PMS2 described in relatively few Lynch Families
6. AMSTERDAM CRITERIA
There should be at least three relatives with an
HNPCC-associated cancer (colorectal cancer,
cancer of the endometrium, small bowel, ureter, or
renal pelvis)
One should be a first degree relative of the other
two
At least two successive generations should be
affected
At least one should be diagnosed before age 50
Familial adenomatous polyposis should be
excluded in the colorectal cancer case(s) if any
Tumors should be verified by pathological
examinationVasen, HF, Watson, P, Mecklin, JP, et al. Gastroenterology 1999; 116:1453
7. BETHESDA CRITERIA
1. Colorectal cancer diagnosed in a patient who is less
than 50 years of age.
2. Presence of synchronous, metachronous colorectal,
or other HNPCC-associated tumors*, regardless of age.
3. Colorectal cancer with the MSI-H•-like histologyΔ
diagnosed in a patient who is less than 60 years of
age◊.
4. Colorectal cancer diagnosed in a patient with one or
more first-degree relatives with an HNPCC-related
tumor, with one of the cancers being diagnosed under
age 50 years.
5. Colorectal cancer diagnosed in a patient with two or
more first- or second-degree relatives with HNPCC-
related tumors, regardless of age.
8. HISTOLOGY
Lynch syndrome associated endometrial cancers are
mostly endometriod
Uterine papillary serous carcinoma, clear cell, and
uterine mixed mullerian subtypes have all been
reported
Usually diagnosed early stage and have favorable
prognosis
Tumor location: Uterine Corpus versus Lower Uterine
Segment
Can be confused with cervical adenocarcinoma
LUS tumors were found to be of higher grade
9.
10. OVARIAN CANCER
Majority Epithelial Papillary Serous
Endometriod, Mucinous and clear cell have been
reported
More likely than general population to be Stage I
or II
No difference in 5 year survival
11. SCREENING
Start at age 30-35 (or 5-10 years prior to index case)
Yearly Endometrial biopsy to screen for endometrial
cancer
Yearly pelvic exam, TVUS, and +/- CA-125 (q6-
12months) to screen for ovarian cancer
12. SUMMARY
Autosomal dominant
Germline mutation of MMR gene
27-71% chance of endometrial cancer
3-14% chance of ovarian cancer
Risk reducing surgery after childbearing
If undergoing surgery for colorectal cancer should be offered
concurrent risk reducing surgery
Annual EMB for screening endometrial cancer
Annual pelvic exam, TVUS, q6-12 month CA-125
Oral contraceptives for premenopausal chemoprevention
Hinweis der Redaktion
In women with Lynch syndrome, the lifetime risk of endometrial cancer is 27 to 71 percent compared with 3 percent in the general population (figure 1) [5,6]. Risk is between 27 and 60 percent for women with MLH1 and MSH2 mutations and 60 to 71 percent for those with mutations in MSH6. The mean age at endometrial cancer diagnosis in women with Lynch syndrome is 46 to 54 years, compared with a mean age of 60 years in other women [15-18]. Some women with Lynch syndrome may develop endometrial cancer before age 40. As an example, in a study that included 69 women with Lynch syndrome-associated endometrial cancer, 18 percent were diagnosed under the age of 40 years
The revised Bethesda guidelines for testing colorectal tumors for microsatellite
Also similar to women with sporadic endometrial cancer, the majority of Lynch syndrome-associated endometrial cancers are diagnosed with early stage disease and, thus, have a favorable prognosis [16,17]. As an example, a study in women with endometrial cancer that matched for age at diagnosis and cancer stage found similar five-year survival in 50 women with Lynch syndrome and 100 matched controls (88 versus 82 percent) [16].
Endometrial tumor location, however, may differ in some women with Lynch syndrome. Endometrial cancer arises most commonly in the uterine corpus rather than the lower uterine segment (LUS) in all women, but in Lynch syndrome, there appears to be a higher proportion of LUS tumors. These tumors can be misdiagnosed as cervical adenocarcinoma. The largest series to investigate this included over 1000 women with endometrial cancer; 10 of 35 of the LUS tumors were found in women with Lynch syndrome [21]. LUS tumors were higher grade and more invasive than corpus cancer. Thus, although LUS tumors account for a small number of Lynch-associated endometrial cancers, a finding of tumor at this site should prompt risk assessment for Lynch syndrome (see 'Genetic testing for Lynch syndrome' above).
Lifetime risk for colon, endometrial and ovarian cancer in individuals compared with the general population.
Ovarian cancer — The lifetime risk of ovarian cancer in women with Lynch syndrome is 3 to 14 percent compared with 1.5 percent in the general population (figure 1) [5,6]. Women with Lynch syndrome develop ovarian cancer younger than other women (43 to 50 versus 60 years old) [22,23
TAH/BSO and chemoprevention
Weak recommendation: Benefits and risks closely balanced and/or uncertain
Low-quality evidence: Evidence from observational studies, unsystematic clinical observations, or from randomized trials with serious flaws