Activity of capecitabine for central nervous system metastases from breast cancer

Central nervous system (CNS) metastases are a significant burden in breast cancer (BC). Capecitabine is a frequent choice in this scenario, but data supporting its single-agent activity are scarce. We aimed to evaluate the intracranial efficacy of capecitabine in CNS metastases from BC.

This retrospective cohort included patients with CNS metastases from BC treated with capecitabine at a single centre. Study endpoints were intracranial CNS objective response rate (CNS-ORR), intracranial CNS disease control rate (CNS-DCR), intracranial CNS progression-free survival (CNS-PFS) and overall survival (OS).

209 patients were included; 41.6% hormone receptor-positive HER2-negative (HR + HER2-), 33.9% human epidermal growth factor receptor 2 positive (HER2+), and 26.4% triple-negative breast cancer (TNBC). Radiotherapy was performed in 90.4% and CNS surgery in 27.5%. Among patients accessible for intracranial response, 3-month CNS-ORR and CNS-DCR were 41.6% and 81.2%. CNS-ORR was numerically higher among TNBC (61% versus 38% in HR + HER2-BC and 35% in HER2 + BC) (p = 0.194). When considering patients who were not evaluable at 3-month as non-responders, the 3-month CNS-ORR was 19.1% (18.4% in HR + HER2-, 18.3% in HER2+, and 21.6% in TNBC). Nevertheless, TNBC was associated with lower CNS-PFS (p < 0.001) and OS (p < 0.001). Median PFS was 8.3 months in HR + HER2-, 5.0 months in HER2+, and 3.0 months in TNBC. Median OS was 8.7, 9.1 and 4.5 months, respectively.

Among patients with BC and CNS metastases accessible for intracranial response at 3 months, intracranial activity was observed with capecitabine. These patients have a poor prognosis regardless of the BC subtype, especially in scenarios where newer therapeutic options are unavailable.