ADJUVANT CHEMOTHERAPY OF PRIMARY OPERABLE LUMINAL B BREAST CANCER WITHOUT OVEREXPRESSION OF HER2/NEU IN POSTMENOPAUSAL WOMEN: YES OR NO?

Abstract

Background. Luminal tumors account for 65 % of all breast cancer (BC) cases; however, within this group, there are multiple subtypes with various clinical and morphological characteristics, disease course and prognosis. Choosing an optimal strategy for adjuvant chemotherapy (ACT) in postmenopausal women with primary operable luminal BC B subtype without overexpression of HER2/neu appears to be the most challenging. Objective: to evaluate treatment outcomes in postmenopausal women with primary operable luminal BC without overexpression of HER2/neu depending on the ACT used. Materials and methods. We analyzed treatment outcomes in 190 postmenopausal women with stages T1–2N0–1M0 primary operable luminal BC without overexpression of HER2/neu. Of them, 105 patients had luminal BC A subtype, whereas 50 patients were diagnosed with luminal BC B subtype. All patients underwent radical mastectomy or organ-preserving surgery + external beam radiotherapy + adjuvant hormonal therapy with tamoxifen or aromatase inhibitors; 35 patients with luminal BC B subtype additionally had 6 cycles of FAC ACT. Results. We observed no significant differences in overall and relapse-free survival (assessed using the Kaplan–Meier method) across the groups during 37 months of follow-up (p >0.05). Conclusions. Luminal BC B subtype without overexpression of HER2/neu is an extremely heterogeneous group in terms of planning ACT, especially in postmenopausal women. Our results encourage to pay particular attention to finding additional biological characteristics of the tumor, which will ensure more individual approach to treatment of these patients.