Consequences of universal MSI/IHC in screening ENDOMETRIAL cancer patients for Lynch syndrome.

OBJECTIVE: Determine factors impacting the uptake of genetic counseling and results of genetic testing following universal tumor testing for Lynch syndrome in patients with endometrial cancer. METHODS: The study population consisted of two unselected cohorts of endometrial cancer patients, 408 identified retrospectively and 206 identified prospectively. Immunohistochemistry for mismatch repair protein expression and/or microsatellite instability analysis was performed on these tumors. MLH1 methylation analysis was performed on tumors with loss of MLH1 protein. Tumor studies were considered suggestive of Lynch Syndrome if they showed immunohistochemical loss of MSH2, MSH6 or PMS2, loss of MLH1 without MLH1 promoter methylation, and/or microsatellite instability. Participants with suggestive tumor studies were contacted and offered genetic counseling and testing. RESULTS: In the retrospective cohort, 11% had tumor studies suggestive of Lynch syndrome, and 42% was seen for genetic counseling. A germline mutation was detected in 40%, and one had a variant of uncertain significance. In the prospective cohort, 8.7% of patients had tumor testing suggestive of Lynch syndrome; 72% were seen for genetic counseling. Germline mutations were found in 40%, and one had a variant of uncertain significance. Common challenges included timing of re-contact, age, perceived lack of relevance, inability to travel and limited insurance coverage. CONCLUSIONS: There are several barriers to genetic counseling and testing follow-up after universal tumor testing, and uninformative genetic test results present a management challenge. It is important to consider these limitations when implementing an approach to screening endometrial cancer patients for Lynch syndrome.

Outcomes of screening endometrial cancer patients for Lynch syndrome by patient-administered checklist.

OBJECTIVE: The aims of this study were to implement a patient-administered checklist designed to identify endometrial cancer patients at elevated risk for Lynch syndrome; measure subsequent genetic counseling and testing; and identify differences between those who attended genetic counseling and those who did not. METHODS: We developed a 4-item yes/no checklist of personal and family history risk factors for Lynch syndrome-associated endometrial cancer and recommended referral for genetic counseling for patients meeting any of the criteria. Retrospective chart review was performed to determine subsequent genetic counseling and testing outcomes over a 15 month period. RESULTS: 6/387 (1.6%) of endometrial cancer patients tested positive for a Lynch syndrome mutation. 4/24 (17%) of endometrial cancer patients who met referral criteria and attended genetic counseling tested positive. 38/70 (55%) of patients who met referral criteria were not seen for genetic counseling. Patients who were diagnosed with endometrial cancer at younger ages, who had primary surgery at our institution, or who met more than one referral criteria were more likely to be seen for genetic counseling. CONCLUSIONS: Endometrial cancer patients who met referral criteria and attended genetic counseling comprised a population enriched for Lynch syndrome. This approach allowed Lynch syndrome evaluation resources to be targeted to a population of patients that is high risk and interested in the information. The referral rate of at-risk patients needs to be improved, and allocating resources towards this goal could increase the identification of Lynch syndrome while avoiding some of the pitfalls of universal screening.

Underestimation of risk of a BRCA1 or BRCA2 mutation in women with high-grade serous ovarian cancer by BRCAPRO: a multi-institution study.

PURPOSE: Identification of the 10% to 15% of patients with ovarian cancer who have germline BRCA1 or BRCA2 mutations is important for management of both patients and relatives. The BRCAPRO model, which estimates mutation likelihood based on personal and family cancer history, can inform genetic testing decisions. This study's purpose was to assess the accuracy of BRCAPRO in women with ovarian cancer. METHODS: BRCAPRO scores were calculated for 589 patients with ovarian cancer referred for genetic counseling at three institutions. Observed mutations were compared with those predicted by BRCAPRO. Analysis of variance was used to assess factors impacting BRCAPRO accuracy. RESULTS: One hundred eighty (31%) of 589 patients with ovarian cancer tested positive. At BRCAPRO scores less than 40%, more mutations were observed than expected (93 mutations observed v 34.1 mutations expected; P < .001). If patients with BRCAPRO scores less than 10% had not been tested, 51 (28%) of 180 mutations would have been missed. BRCAPRO underestimated the risk for high-grade serous ovarian cancers but overestimated the risk for other histologies (P < .001), underestimation increased as age at diagnosis decreased (P = .02), and model performance varied by institution (P = .02). CONCLUSION: Patients with ovarian cancer classified as low risk by BRCAPRO are more likely to test positive than predicted. The risk of a mutation in patients with low BRCAPRO scores is high enough to warrant genetic testing. This study demonstrates that assessment of family history by a validated model cannot effectively target testing to a high-risk ovarian cancer patient population, which strongly supports the recommendation to offer BRCA1/BRCA2 genetic testing to all patients with high-grade serous ovarian cancer regardless of family history.