Abstract P1-12-06: Factors related to the prognosis of breast cancer patients after the development of brain metastases

Abstract

Abstract Background: Brain metastases (BM) are a serious relatively common complication of breast cancer (BC). We evaluated prognostic factors for survival after diagnosis of BM from BC in a contemporary cohort of pts. Methods:Pts diagnosed with BM from BC between 1999 and march 2016 and treated at the Istituto Oncologico Veneto of Padua were evaluated. Overall survival (OS) was defined as time from BM diagnosis to death or last follow-up. Pts were classified in 4 categories according to the breast cancer-specific Graded Prognostic Assessment (GPA) index according to validated criteria (Sperduto et al, 2012), based on age, Karnofsky Performance Status (KPS) and BC phenotype. Cox proportional models were used to calculate HR and 95% CI. Results: 199 pts were identified. Median age at BM diagnosis was 56 yrs (range 28-84). Tumor phenotype distribution was as follows: triple negative (TN, 20.1%), hormone receptor (HR)-HER2+ (16.8%), HR+HER2+ (24.0%) and HR+HER2- (39.1%). Median time to BM diagnosis was 48.9 months (range 0-327), with significant differences according to tumor phenotype (median 27.3, 31.8, 46.1 and 55.2 months in TN, HR-HER2+, HR+HER2+, HR+HER2-, respectively, p=0.009). With respect to OS, no significant difference was observed across tumor phenotypes, with TN patients experiencing the worse outcome (median: 4.7, 7.7, 11.0 and 6.2 months in TN, HR-HER2+, HR+HER2+, HR+HER2-, p=0.187). The breast-specific GPA index, which combines tumor phenotype with patient-related features, was significantly associated with OS (Table). The number of local treatment received (radiotherapy, either whole brain or stereotactic, or neurosurgery) and the administration of systemic treatment after BM diagnosis were significantly associated with better OS (Table). Patients in the less favorable GPA category (GPA index <1) were less likely to receive systemic treatment after BM diagnosis compared to other GPA categories (43% vs 71%, p=0.009); no association between GPA category and local treatment was observed. Patients undergoing increased lines of local treatments where more likely to receive systemic therapy (chi2 square test p<0.001). To avoid bias we performed two separate multivariate analyses including: i) GPA category and number of local treatments; ii) GPA category (patients with GPA index <1 excluded) and systemic treatment. GPA maintained a significant prognostic value in both models (p=0.002 and p=0.038, respectively). Both local and systemic treatments added independent prognostication beyond GPA (Table). Prognostic factorsMedian OS, months (95%CI)HR (95%CI), univariatep, univariateHR (95%CI), corrected for GPAGPA category 3.5-418.8 (15.2-22.5)ref -2.5-38.8 (3.8-13.8)1.40 (0.80-2.43) -1.5-25.5 (3.5-7.5)1.76 (1.00-3.10) -0-1.02.7 (1.2-4.3)2.67 (1.35-5.28)0.019-Number of local tretaments received 03.0 (1.8-7.5)ref ref18.0 (5.8-10.3)0.53 (0.38-0.74) 0.54 (0.38-0.78)221.3 (15.2-27.3)0.36 (0.20-0.65) 0.49 (0.26-0.93)335.5 (33.5-37.6)0.12 (0.04-0.38)<0.0010.08 (0.02-0.33)Systemic treatment yes13.1 (8.7-17.4) no2.6 (1.3-3.8)0.42 (0.30-0.58)<0.0010.46 (0.31-0.68) Conclusions: Patient-related features, tumor phenotype and multimodal treatments all independently contribute to modulate the prognosis of pts with BM from BC. Citation Format: Griguolo G, Dieci MV, Giarratano T, Giorgi CA, Orvieto E, Ghiotto C, Falci C, Mioranza E, Tasca G, Milite N, Miglietta F, Conte P, Guarneri V. Factors related to the prognosis of breast cancer patients after the development of brain metastases [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P1-12-06.