Prognostic factors influencing the selection of bevacizumab combined with chemotherapy in patients with HER2-negative metastatic breast cancer in routine clinical practice: Oncosur-Avalox—Observational cross-sectional study.

Abstract

e12020 Background: Combining bevacizumab (BEV) with chemotherapy (CT) improves survival in HER2-negative metastatic breast cancer (MBC). We investigated the influence of age, ECOG, hormonal status, number of sites, location of metastases and patient decision on the selection of BEV combined with CT in MBC. Methods: Observational cross-sectional multicenter study in patients with HER2- negative MBC who have received first-line CT with BEV. Results: 219 patients were included: median age 51(44-63) yr; ECOG: 0=53%; 60.4% pre-menopausic; 23.9% triple-negative (TN);76.2 % hormone receptor positive (HR+).Metastatic disease: ≥3 sites=39.2% (TN: 22%; HR+: 43.9%); location: 45.2% bone, 37.4% liver, 30.1% lung. Most frequent BEV combinations were paclitaxel/BEV(60.7%) and docetaxel/BEV(12.8%); median no. of CT cycles: 6 (5- 8). A disease-free survival (DFS) ≥12 months was achieved by 82.8%; TN: 78.9%; HR+: 83.3%. Overall response rate (ORR) was 62.7%: 53.6% partial response (PR), 9.1% complete response (CR); 25.4% stable disease (SD) and 7.2% disease progression (4.8% non evaluated). TN:ORR 54.2% (47.9% PR), clinical benefit 80% (27.1% SD); HR+:ORR 65.8% (55.7% PR), clinical benefit 89.9% (24.1% SD). 66.2% presented at least one toxicity, mainly grade 1-2; 32% BEV-related: only 3 grade 3 toxicities; no grade 4. Receiving adjuvant hormonal therapy was associated to DFS ≥12 months (p<0.05). ER+ tumors (OR:0.326;95%CI:0.16-0.65;p=0.002) and patient decision after consider doctor opinion (OR:0.026;95%CI:0.01-0.74; p=0.085) were independent factors associated with the selection of paclitaxel-BEV in the overall population (TN or HR+). Liver metastases were significantly related to paclitaxel-BEV administration (p<0.01). Conclusions: First-line CT with BEV is an effective and safe scheme for patients with TN and HR+ MBC. ER+ tumors and patient decision after consider doctor opinion were identified as independent factors for the selection of paclitaxel-BEV therapy. The presence of liver metastases was significantly associated to the administration of a paclitaxel-BEV regimen.