Abstract P6-08-24: Family history of pancreatic cancer and the prevalence of pathogenic germline variants in a contemporary cohort of newly diagnosed breast cancers
Authors: Wang Annie , Everett Jessica , Chun Jennifer , Kaplowitz Elianna , Simeone Diane , Schnabel Freya 
Published: March 2020

Introduction: Several studies have found a relationship between familial breast cancer (BC) and pancreatic cancer (PC). Known genes associated with both BC and PC include BRCA1, BRCA2, PALB2, ATM, STK11, and possibly others. For carriers of pathogenic germline variants (PGVs) in these genes with family history of PC (FHPC), pancreas surveillance is recommended and can lead to an earlier detection of disease. Current genetics practice typically involves use of multi-gene panel (MGP) testing covering all of these genes linked to both cancers, but not all patients have had complete testing leading to likely under appreciation of PC risk in BC cohorts. With improved treatment options and survival for BC and ovarian cancer in PGV carriers, we may begin to observe an increased prevalence of PC in this group. The purpose of our study was to evaluate the clinicopathologic characteristics including genetic testing uptake and outcomes in BC patients with and without a family history of pancreatic cancer (FHPC).

Methods: We queried the Institutional Breast Cancer Database, which includes patients diagnosed with BC between January 2010 and December 2018. Variables analyzed included FHPC in a first or second-degree relative, and other clinical and tumor characteristics. Statistical analyses included Pearson’s Chi Square and logistic regression.

Results: A total of 232 BC patients (7%) had a positive FHPC, including 115 (50%) with a first-degree relative and 117 (50%) with other relatives affected. When comparing BC patients with and without any FHPC, those with FHPC were 1.93 times more likely to be of White race (p&lt;0.001), and 1.68 times more likely to have undergone genetic testing (p&lt;0.001). Genetic testing in those with FHPC included BRCA1/2 only for 33%, multi-gene testing for 23%, and no genetic testing in 44% PGVs were identified in 9/129 (7%) tested patients including 2 BRCA1, 6 BRCA2, and 1 PALB2. Age, previous history of BC or other cancer, surgery type, tumor stage, histology, size, grade, and ER/PR/HER2neu status were not statistically different between the patients who had FHPC versus no FHPC. The 4% rate of BC recurrence was the same in both groups.

Conclusions: Within a contemporary cohort of newly diagnosed breast cancer patients, 7% had a positive FHPC. Although these patients were more likely than those without FHPC to have genetic testing, the majority, 77%, had incomplete or no genetic testing suggesting likely under-diagnosis of PC risk. Our study underscores the importance of querying and documenting FHPC in patients with BC and the consideration of germline testing and evaluation for pancreas surveillance in these patients and their family members.

Citation Format: Annie Wang, Jessica Everett, Jennifer Chun, Elianna Kaplowitz, Diane Simeone, Freya Schnabel. Family history of pancreatic cancer and the prevalence of pathogenic germline variants in a contemporary cohort of newly diagnosed breast cancers [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-08-24.