Influence of breast cancer subtype on pathological complete response

Abstract

Objective: To compare the rates of pathological complete response (pCR) after treatment with neoadjuvant chemotherapy, in the different subtypes of breast cancer in patients followed at the Mastology Service of Hospital do Servidor Público Estadual. Methods: Descriptive and retrospective study, in which medical records of 213 patients diagnosed with breast cancer and submitted to neoadjuvant chemotherapy were reviewed, from February 2011 through January 2018. Histological data collected were: hormone receptors, hyperexpression of HER-2, grade, histological type and clinical data: age of the patient at diagnosis, tumor size and clinical stage at diagnosis and after chemotherapy, and rate of pCR. Results: The mean age of patients at diagnosis was 53.97 years. Forty-six patients (21,6%) had pCR, 77 (36.1%) were grade 2 and 136 (63.9%) were grade 3. Regarding cancer subtype, 29 patients (13.6%) were reported to have pure HER2 subtype, 48 patients (22.5%) corresponded to Luminal A subtype, 51 (23.9%) to Luminal B, and 66 patients (31.0%) were characterized as Triple Negative, while only 17 patients (7.9%) had Luminal B HER. Conclusion: The subtypes Pure HER 2 and Luminal B had the highest pCR rates.

Integrative review of clinical trials and meta-analysis of the main studies of neoadjuvant chemotherapy in the treatment of breast cancer in the past 30 years

“…Failure to PCR is related to unfavorable prognosis in TNBC and HER-2+ tumors, but not in most luminal patients 29 . In fact, studies have indicated that luminal patients tend to present a favorable prognosis, although they are less responsive to chemotherapy, with relatively lower chances of achieving PCR, thus reflecting the uncertain correlation between PCR and long-term outcomes in luminal patients 16 .…”

“…Factors related to the highest probability of PCR include TNBC tumors, HER-2+, high rate of cell proliferation (Ki67), and high degree of nuclear and ductal histology. Usually, patients with positive hormone receptor (RH+) have worse rates of PCR 12,29,30 . Currently, the rates of PCR are higher in TNBC patients, reaching 64.8% due to the use of immunotherapy with Pembrolizumab combined with chemotherapy 27 , and in HER-2+ due to double blockage with trastuzumab and pertuzumab associated with chemotherapy 20 (Table 3).…”