Factors Affecting Treatment Outcome of Metastatic Breast Cancer: Single Institution Study

Abstract

BACKGROUND: Metastatic breast cancer (MBC) is an incurable disease. AIM: The goal of therapy is to prolong survival and amelioration of quality of life. However, the benefit of later systemic treatment lines is not clear. METHODS: This was a retrospective study of 345 MBC patient., assessment of progression free survival (PFS) survival with first line of treatment and second, third, fourth, fifth, and sixth lines of therapy, and analysis of different prognostic factors. RESULTS: The median overall survival (OS) was 31.7 month. The median PFS was 8.1 versus 3 month for first line of treatment and beyond. Where median PFS1, PFS 2, PFS 3, PFS 4, PFS 5, and PFS 6 were 8.1, 5.8, 3.8, 4.8, 3.4, and 2.6, respectively. PFS of first line was significantly prolonged in hormone positive luminal subtype, bone only metastasis, age above 35, ECOG I-II, and oligometastatic (p = 0.041, 0.038, 0.023, 0.034, 0.0001, and 0.001, respectively). Post-progression survival was 23.4 months and it was significantly prolonged in hormone positive luminal subtype, bone only metastasis, age above 35, ECOG I-II and PFS more than 6 months with first line. CONCLUSION: PFS is reduced with using more treatment lines in MBC. Patients with luminal subtype, bone only metastasis, age above 35, ECOG I-II, and PFS more than 6 months with first line may have the best benefit from later lines.