Is local recurrence higher among patients who downstage to breast conservation after neoadjuvant chemotherapy?

Abstract

BACKGROUND:In early studies, local recurrence (LR) rates were higher after neoadjuvant chemotherapy (NAC) in comparison with upfront surgery. Modern outcomes are uncertain, particularly among those who are initially breast-conserving surgery-ineligible (BCSi) and downstage to being breast-conserving surgery-eligible (BCSe). METHODS: Among patients with cT1-3 breast cancer treated from 2014 to 2018 who were BCSe after NAC, clinicopathologic characteristics and LR were compared between initially BCSe patients and BCSi patients who downstaged. Breast-conserving surgery (BCS) eligibility was determined prospectively. RESULTS: Among 685 patients, 243 (35%) were BCSe before and after NAC and had BCS; 282 (41%) were BCSi before NAC, downstaged to BCSe, and had BCS; and 160 (23%) were BCSi before NAC, downstaged to BCSe, and chose mastectomy. The median age was 52 years, and most cancers were cT1-2 (84%), cN+ (61%), and human epidermal growth factor receptor 2-positive (HER2+; 38%) or triple-negative (34%). Those who were BCSe before NAC had a lower cT stage, whereas those who chose mastectomy were younger (P < .05). NAC was usually ACT (doxorubicin, cyclophosphamide, and a taxane)-based (92%), 99% of HER2+ patients received dual blockade, and 99% of BCS patients received adjuvant radiation. At a median follow-up of 35 months, 22 patients (3.2%) had developed LR. The Kaplan-Meier 4-year LR rates were not different among the groups (1.9% for those who were BCSe before and after NAC, 6.3% for those who downstaged to being BCSe and underwent BCS, and 2.7% for those who downstaged and underwent mastectomy; P = .17). CONCLUSIONS: LR rates are low after NAC and BCS, even among BCSi patients who downstage, and they are not improved in patients who downstage and choose mastectomy. Mastectomy can be safely avoided in BCSi patients who downstage with NAC.

Breast Conservation Surgery and Mastectomy have Similar Locoregional Recurrence Following Neoadjuvant Chemotherapy

“…Our findings are consistent with a recently published single institution series showing that LRR risk is largely driven by tumor biology and not the type of surgery. 9,10 While earlier studies seem to show an increased risk of LRR in patients receiving NAC, current results may reflect improvements in systemic therapies (chemotherapy, HER2-directed therapy, and endocrine therapy) as well as differences in imaging that help to select appropriate candidates for BCS.…”

“…However, other analyses have shown no increased risk of local failure 6–8 . Two recent single institutional series reported no increase in LRR among patients undergoing BCS compared with mastectomy after NAC, with both finding that LRR risk was related to clinical and tumor features, such as clinical stage, receptor subtype, presence of lymphovascular invasion, or lack of pathologic complete response (pCR) 9,10 . Indeed, several series demonstrate the relationship between tumor biology, lack of pCR, and increased risk of LRR 11–13 .…”

Breast-conserving surgery is not associated with increased local recurrence in patients with early-stage node-negative triple-negative breast cancer treated with neoadjuvant chemotherapy

“…Mamtani et al analyzed a cohort of 685 patients who were BCS-eligible after NACT [ 35 ]. Among these, 282 patients (41%) were initially BCS-ineligible and chose BCT while 160 patients (23%) were initially BCS-ineligible and chose mastectomy.…”

Neoadjuvant systemic therapy for breast cancer

“…Significant geographical variation was also observed, with women in North America eligible for BCS more likely to undergo unilateral and bilateral mastectomy relative to comparable patients in Europe and Asia. These data highlight the importance of conveying to BCS candidates their accurate risk of residual disease and that locoregional recurrence is altered minimally by more extensive surgery 24 .…”