278P Characteristics of endometrial and ovarian cancers in Lynch syndrome and hereditary breast ovarian cancer syndrome

Abstract

Aim/Background: Lynch syndrome and Hereditary Breast Ovarian Cancer (HBOC) syndrome are two hereditary disorders which predispose individuals to gynaecological cancers such as endometrial and ovarian cancer. There may be unique traits in gynaecological cancers arising from these genetic conditions, especially in multi-ethnic populations such as Singapore. We aim to characterize the profiles of endometrial and ovarian cancers in patients diagnosed with Lynch syndrome and the profile of ovarian cancer in patients diagnosed with HBOC in a tertiary institution in Singapore. Methods: Cases of Lynch and HBOC syndromes were identified from a genetic database between January 2006 and July 2015. Results: There were 50 cases of Lynch syndrome. 10 patients had gynaecological cancers (7 endometrial cancers, 1 ovarian cancer and 2 synchronous endometrial and ovarian cancers). The mean age of diagnosis was 42 years for endometrial cancer and 43 years for ovarian cancer. All the endometrial cancers belonged to the endometrioid subtype and were Stage 1 diseases. Of the 3 ovarian cancers, 2 were clear cell subtypes and 1 was endometrioid subtype, varying between Stage I to Stage III diseases; there was also one recurrence after adjuvant chemotherapy. 4 of the 10 patients had genetic testing, 2 had mutations in MLH1 gene, 1 had mutation in MSH2 gene and 1 had mutation in MSH6 gene. There were 60 cases of HBOC syndrome and 12 had ovarian cancer. 3 out of these 12 patients had metachronous breast cancer. The mean age of diagnosis of ovarian cancer in HBOC syndrome was 49 years. 8 had BRCA 1 mutations and 4 had BRCA 2 mutations. The majority (8/12) had serous component in the histological subtype. Most (9/12) were advanced staged at diagnosis and half of the cases (6/12) had recurrences as well. Conclusions: Hereditary endometrial and ovarian cancers tend to be diagnosed at an earlier age. In Lynch syndrome, both cancers appear to be early staged at diagnosis and ovarian cancer was of the non-serous subtypes. In HBOC syndrome, ovarian cancer was predominantly of the serous subtype and more likely to be advanced staged and develop recurrences. Further research is necessary in larger Asian cohorts.