Abstract
Neoadjuvant chemotherapy (NAC) is an integral part of breast cancer treatment. Determination of the factors that can distinguish patients who will have best response to NAC is invaluable. In this study, we aimed to elucidate the factors influencing patient response to NAC. We retrospectively collected data of female patients with non-metastatic breast cancer that had received NAC followed by surgery, admitted to Imam Khomeini hospital between 2015-2019. We investigated the association between various tumor and patients' characteristics with pathologic complete response (PCR). Overall data of 205 female patients were collected. PCR was observed in 27.6% of cases. PCR rate in luminal A, luminal B, HER2 enriched, and TNB tumors was reported in 11.1%, 30.2%, 35.7%, and 36.4% of patients respectively (P=0.27). In patients with luminal B tumors, PCR was more prevalent in patients with positive HER2 only (P=0.006). In our study factors which was significantly associated with PCR were: tumor grade, progesterone receptor (PR) status, and HER2 status. In the multiple regression model, positive PR in the tumor lowered the odds of pathologic response 3.6 times (P=0.004). In our study, tumor grade, PR status, and HER2 status was associated with response to NAC. PCR was more prevalent in non-luminal tumors; however, PCR rate in luminal B patients-especially those with HER2 positive status- was slightly less than non-luminals.
Highlights
Breast cancer is the most prevalent site-specific malignancy among women worldwide.[1,2,3] In Iran, breast cancer is the most prevalent female malignancy, with an incidence of 31 per 100 000, accounting for 27% of all new cancer cases in females; it is the second cause of cancer-related deaths in this country with a mortality rate of 8.7 per 100 000 in 2018.4Neoadjuvant therapies have been introduced in to breast cancer management since the 1970s;5 they were initially intended to downstage inoperable disease to make it operable, and subsequently their use extended to operable breast cancers, allowing less extensive surgery of the breast and axilla.[5]
Several benefits are proposed for neoadjuvant chemotherapy (NAC): the chance to observe the response of intact tumor to several agents[2,6,7]; providing some valuable prognostic information like pathologic complete response (PCR) to NAC2,3,6-10; probable tumor shrinkage, converting inoperable disease to operable or allowing the surgeon and patient to pursue less invasive surgeries.[5,7,10]
There are some suggested drawbacks for neoadjuvant compared to adjuvant chemotherapy, such as the probable increased risk of local recurrence after breast conserving surgery due to inaccurate localization.[5]
Summary
Breast cancer is the most prevalent site-specific malignancy among women worldwide.[1,2,3] In Iran, breast cancer is the most prevalent female malignancy, with an incidence of 31 per 100 000, accounting for 27% of all new cancer cases in females; it is the second cause of cancer-related deaths in this country with a mortality rate of 8.7 per 100 000 in 2018.4Neoadjuvant therapies (including chemotherapy) have been introduced in to breast cancer management since the 1970s;5 they were initially intended to downstage inoperable disease to make it operable, and subsequently their use extended to operable breast cancers, allowing less extensive surgery of the breast and axilla.[5]. Some of the most important factors that have been proposed to affect tumor response positively include: HER2-enriched and triple negative (TN) tumor subtypes, younger age, smaller tumor size; higher grade, presence of lymphovascular invasion, and high Ki67 level.[1,3,5,6,9,10] In this study, we retrospectively collected the data of female patients with non-metastatic breast cancer who underwent NAC followed by surgery. The purpose of this study was to investigate the effect of different patient and tumor factors, especially tumor receptor status and tumor subtypes, on PCR to NAC.
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