Abstract PD7-04: Capecitabine treatment for patients with central nervous system metastases from breast cancer
Authors: Gouveia Mariana , Filho Cássio Murilo Hidalgo , Bonadio Renata Colombo , Testa Laura 
Published: March 2023

BACKGROUND: Central nervous system (CNS) is a common site of metastases from breast cancer (BC). The efficacy of systemic therapy for CNS metastases from HER2-negative BC is limited. Although new anti-HER2 therapies seem to be more effective in this scenario, these drugs are not widely available yet. Chemotherapy with capecitabine if often used in patients (pts) with CNS metastases, but data supporting its activity is scarce. We aimed to evaluate the effectiveness of capecitabine for CNS metastases from BC.

METHODS: This retrospective study included pts with BC and confirmed CNS metastases treated with capecitabine at a tertiary cancer center from 2010-2021. Study endpoints included intracranial objective response rate (CNS-ORR) and intracranial disease control rate (CNS-DCR), intracranial progression-free survival (CNS-PFS), and overall survival (OS). Survival analysis were estimated by Kaplan-Meier method and compared using log-rank test.

RESULTS: Among 209 pts included, 41.6% were hormone receptor-positive (HR+) HER2-negative 33.9% HER2-positive, and 26.4% triple-negative (TNBC). Most pts had ECOG 0-1 (56.9%) and had received &lt; 2 chemotherapy lines (77.9%) before capecitabine. Brain parenchymal metastases were present in 85.5%; 43.1% had ≥ 5 brain lesions. Radiotherapy was performed in 90.4% of the cases and CNS surgery in 27.5%. Among 124 pts accessible for intracranial response, CNS-ORR and CNS-DCR were 31.4% and 79% in 3-months. In 6 months, 76 pts were accessible, and CNS-ORR and CNS-DCR were 23.6% and 73.6%. The median CNS-PFS was 5.6 months and median OS was 7.9 months. Table 1 shows CNS-ORR and CNS-DCR at 3 months according to immunohistochemical subtype. Although TNBC had higher 3-month IORR (48%), this subgroup had a worse prognosis compared to HR+ (OS: HR = 1.87, CI 95% = 1.28 – 2.73, p = 0.001). mOS was 8.7 months and 9.1 months for HR+ and HER2+ subtypes respectively, and 4.5 months for TNBC. OS was worse in patients with ECOG-PS ≥ 2 (p = 0.017) and was not influenced by the number or size of brain metastases, number of previous chemotherapy lines and previous surgery or radiotherapy to CNS.

CONCLUSION: Our results showed that pts with CNS metastases from BC still have a poor prognosis. TNBC subtype and ECOG-PS ≥ 2 were detrimental prognostic factors. Nevertheless, among pts accessible for intracranial response, satisfactory CNS-DCR was observed with capecitabine, suggesting activity of this drug for selected pts.

Intracranial response rate (CNS-ORR) and disease control rate (CNS-DCR) of central nervous system metastases from breast cancer treated with capecitabine.

Citation Format: Mariana Gouveia, Cássio Murilo Hidalgo Filho, Renata Colombo Bonadio, Laura Testa. Capecitabine treatment for patients with central nervous system metastases from breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD7-04.