Does pathological complete remission after neoadjuvant chemotherapy translate to longer relapse-free survival in patients with triple-negative breast cancer in the Indian population?

Abstract

e12618 Background: Attainment of pathological complete remission (pCR) with neoadjuvant chemotherapy in triple-negative breast cancer (TNBC) is associated with improved survival outcomes. However, data corroborating this fact is lacking from the Indian subcontinent. Methods: We evaluated 179 cases of TNBC, registered at Dr. B.R.A., I.R.C.H., AIIMS, New Delhi, from a period of May 2013 to July 2020, who were treated with neo-adjuvant chemotherapy (NACT) followed by surgery. Patients with oligometastatic disease who were treated with NACT with curative intent were also included in the analysis. Multivariate logistic regression analysis was done to explore the factors associated with the achievement of pCR. Survival analysis was done to study the correlation of pCR with relapse-free survival (RFS) and overall survival (OS). Results: The median age of our cohort was 43 (18-67) years. Study population comprised 104 (58.1%) pre-menopausal, 67 (37.4%) post-menopausal and 8(4.5%) peri-menopausal patients respectively. Twenty-three patients (12.9%) presented with early breast cancer, 144 (80.5%) were locally advanced and 12 (6.7%) were oligo-metastatic. Forty (22.4%), 127 (71.0%) and 12 (6.7%) patients were at clinical stages-II, III, and IV respectively at the time of presentation as per AJCC 7th edition. The median duration of symptoms was 4 (0.25-36) months. Forty-seven (26.3%) patients underwent breast conservation surgery and 128 (71.5%) patients had modified radical mastectomy. Overall pCR was attained in 29.6%(n=53) of the patients, with rates of 55%(n=22) and 23.6%(n=30) in patients with stage-II and stage-III respectively. Stage-II patients were more likely to achieve pCR after NACT [OR (95% CI: 4.3 (2.0-8.9)] when adjusted for other clinical covariates. Three-year RFS in patients achieving pCR was 94.7%, whereas in patients not achieving pCR was 43.9%, with a hazard of relapse or death significantly less in patients attaining pCR [HR (95% CI): 0.14 (0.06-0.37), p <0.0001]. Similarly, three-year OS was 97.4 % vs 73.8% in patients attaining pCR vs not attaining pCR, with a hazard of death significantly less in patients with pCR [HR (95% CI): 0.06 (0.01-0.45) p<0.006]. Conclusions: Our results confirm that attainment of pCR following NACT leads to better survival outcomes in TNBC. Factors associated with improved pCR rates in the Indian population needs further evaluation.