Outcome of neoadjuvant treatment in triple-negative breast cancer in a rural underserved community.

Abstract

e12608 Background: Complete pathological response (pCR) is a surrogate of successful neoadjuvant treatment of triple-negative breast cancer (TNBC). We extended our study from 2016, where we discussed unusually high pCR employing taxane/platinum (T/P) without the use of adriamycin and cyclophosphamide (AC). Methods: This is a retrospective observational study of an underserved, low income, rural population in Oroville, California over 10 years (2011-2021). Neoadjuvant chemotherapy was offered to eighteen women with ages ranging from 36 to 77 years old (mean age is 56). Minimum requirements for evaluation was three cycles administered within 90 days of starting treatment. The primary end point of this study was pCR. We analyzed the relationship between pCR, chemotherapy regimen, proliferation rate of original tumor by Ki-67 and the ratio of neutrophil and lymphocyte (NLR). The two regimens of chemotherapy included both standard AC+T or the alternative treatment with T/P. We grouped Ki-67 to above and below 50% pre-treatment. NLR was grouped between those above and below 3.2. Results: Our study produced a respectable response rate with 12/18 (67%) achieving pCR. There was no difference with or without exposure to anthracyclines. Out of the twelve who achieved pCR, eight (67%) received T/P and four (33%) got AC+T. Ki-67 in all eighteen patients ranged from 2% to 97% with a median of 75%. Ki-67 was >50% in 10/12 (83%) patients who achieved pCR and 3/6 (50%) in those who did not have a response. NLR was a significant predictor for pCR. 8/12 (67%) of patients who experienced pCR had a NLR of <3.2 compared to the 1/6 ( 17%) with no response. The p-value is .0455. Conclusions: Treatment with the alternative regimen of T/P didn’t affect pCR in our population. We hypothesize that some of the beneficial effects of cytotoxics affected the patient’s immunological milieu on top of the direct effect of the malignant clone.