Abstract P2-08-64: Patterns and predictors of early failure in women with triple negative breast cancer
Authors: Nichols EM , Cherng H-R , Rice SR , Hamza M , Murali S , Tkaczuk K , Bellavance E , Cheston SB , Amin N , Rosenblatt P 
Published: May 2019

Introduction: Triple negative breast cancer accounts for approximately 15% of breast cancer in the United States, but behaves much more aggressively. It occurs more commonly in younger, black female patients and death within two years of diagnosis is much more common in this subset of breast cancer compared to hormone receptor positive patients. We see a high proportion of triple negative breast cancer patients in our urban academic comprehensive cancer center and present an evaluation of our patients who develop failures within 12 months of completion of definitive therapy in an effort to optimize screening strategies and therapy for women with triple negative breast cancer treated at our institution.

Materials/Methods: A retrospective database of 198 women with triple negative breast cancer treated at our institution from 2005-2017 was constructed. Patient characteristics are as follows: 100% female, median age of 54 years, 64% black, 40% married, 93% infiltrating ductal carcinoma, 68% grade 3, 18% with lymphovascular space invasion, 7% BRCA mutated, and 3% HIV positive. Stage breakdown is as follows: Stage I (33%), Stage II (47%), Stage III (16%) and Stage IV (4%). Thirty percent of patients had neoadjuvant chemotherapy. Adjuvant chemotherapy was given in 67% of patients. Ninety-eight percent of patients underwent surgical resection, 55% of whom underwent lumpectomy with 61% having sentinel lymph node biopsy. Adjuvant radiation was received in 56% of patients with a median dose of 60 Gy. Chi-square testing was used to compare variables, while logistic regression with Kaplan-Meier estimate was used to calculate overall survival (OS) and freedom from recurrence (FFR).

Results: With a median follow up of 45 months, 33 (17%) documented failures occurred. 63% of patients in this cohort were AJCC 7th edition stages II or III. In the women who suffered failures, these occurred at a median of 16 months after initiation of therapy, with a median OS of 29 months. Complete records including the date of last radiation therapy (signaling completion of definitive treatment) were available for 25 (76%) of patients. 10/25 failures (40%) occurred within 6 months of completion of radiation therapy while 14/25 (56%) occurred within 12 months of completion of radiation therapy. In women who failed within 6 months of completion of definitive therapy, site of first failure was local in 4 and distant in 6 patients. In the four additional patients who failed between 6 and 12 months following completion of definitive RT, all were considered local or locoregional. Univariate and multivariate analyses were performed which in this small group of women did not show any statistically significant predictors of early failure.

Conclusion: This institutional analysis shows that a large proportion of women with TNBC fail within 12 months of completion of definitive therapy with 57% of failures occurring locoregionally and the remainder occurring distantly. This data suggests that consideration of systemic imaging should occur to better detect these failures and additional study is warranted to determine if predictive factors can be identified for therapy escalation.

Citation Format: Nichols EM, Cherng H-R, Rice SR, Hamza M, Murali S, Tkaczuk K, Bellavance E, Cheston SB, Amin N, Rosenblatt P. Patterns and predictors of early failure in women with triple negative breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-64.