Is adjuvant chemotherapy necessary for Luminal A-like breast cancer?

Patients with breast cancer with Luminal-A subtype have a better prognosis but poor chemotherapy response. Chemotherapy is controversial in lymph node-positive patients with Luminal-A subtype. In this retrospective study, we aimed to evaluate the efficacy and benefit of chemotherapy in the Luminal A-like subtype of breast cancer.

Patients diagnosed with breast cancer within 2006 and 2011 were retrospectively evaluated. Patients with pathologically confirmed Luminal A-like breast cancer were analyzed , and were divided in those receiving taxane-based adjuvant chemotherapy and those who did not.

A total of 136 patients with Luminal-A type were included in the study. The 10-year cumulative disease-free survival (DFS) was 85.6 vs 96.7% (p=0.230) for the chemotherapy and non-chemotherapy groups, and overall survival (OS) was 88.6 vs 100%, respectively (p=0.242). The 10-year cumulative DFS was 80 vs 98.1% for the taxane-based chemotherapy group and taxane-free chemotherapy group (p=0.501), while the OS was 87.5 vs 95.2%, respectively (p=0.391). There was a positive correlation between relapse status and lymph node involvement in the multivariate analysis (p=0.031).

Adjuvant chemotherapy in Luminal-A showed no significant difference for DFS and OS. Taxane-based chemotherapy did not demonstrate any benefit for OS and DFS with relatively more advanced stage and lymph node involvement. We believe that adjuvant chemotherapy plays a minor role in a significant proportion of Luminal-A subtype of breast cancer.