Gemcitabine with carboplatin in metastatic breast cancer: Characterizing outcomes in a modern, real-world population.

Abstract

e13085 Background: The specifics of the salvage regimen gemcitabine/carboplatin (G/C) in metastatic breast cancer (MBC) are not well-characterized and are limited to the clinical trial setting, which often excludes heavily pretreated patients with high disease burden and velocity. The primary objective of this study is to assess real-world outcomes in patients with MBC treated with G/C. Methods: A retrospective chart review was conducted on adults with MBC who received >1 dose of G/C at Emory Healthcare / Winship Cancer Institute from December 1, 2005 to April 30, 2019 (n = 109). Patients were stratified by receptor status (hormone receptor (HR), triple-negative (TN), and human epidermal growth factor receptor-2 (HER2)). Results: Patients were heavily pretreated (median 2 lines, range 0-11) and had extensive metastatic disease (median 3 sites, range 1-6). The median starting doses were carboplatin AUC 2 (range: 1.5-5) and gemcitabine 1000 mg/m2 (range 400-1100). The median cycle length was 21 days (range 14-28). The median progression-free survival (mPFS) was 3.7 months and median overall survival (mOS) was 7.7 months. OS at 24 months was 23.1%. Previous immunotherapy, radiation for palliation, or historical receipt of neoadjuvant/adjuvant cytotoxic therapy was significantly associated with improved survival outcomes, while possessing lung, liver, or bone metastases was significantly associated with worse survival outcomes. The presence of brain metastases did not correlate with outcomes. Side effect/intolerance led to dosing and scheduling adjustments in 38.5% and 49.5% of patients, respectively, and resulted in treatment discontinuation in 21% of patients. Hospitalization occurred in 51.4% of patients on treatment. Conclusions: G/C is a safe and effective regimen in real-world MBC patients regardless of receptor subtype. Even low doses of G/C may provide some CNS penetration and control. Improved survival outcomes associated with previous immunotherapy and radiation for palliation may be due to disease control or carry over effect and warrant further study. [Table: see text]