How Effective is Neoadjuvant Endocrine Therapy (NET) in Downstaging the Axilla and Achieving Breast-Conserving Surgery?

Abstract

Introduction.-NET is effective in downstaging large hormone receptor positive (HR+) breast cancers (BCs) and increasing rates of breast-conserving surgery (BCS), but data regarding nodal pathological complete response (pCR) are sparse. We compared nodal and breast downstaging with NET, and axillary response rates after NET and neoadjuvant chemotherapy (NAC).Methods-Consecutive stage I-III BC patients treated with NET and surgery from 1/2009-12/2019 were identified from a prospectively maintained database. Nodal pCR rates were compared between biopsy-proven node-positive patients treated with NET, and HR+/HER2− patients treated with NAC from 11/2013-07/2019.Results.-127 cancers treated with NET and 338 with NAC were included. NET recipients were older, more likely to have lobular and lower-grade tumors, and higher HR expression. With NET, the nodal pCR rate was 4/38 (11%) of biopsy-proven cases, and the breast pCR rate was 2/126 (1.6%). Nodal-downstaging rates with NET and NAC were not significantly different (11% versus 18%,P=0.37). Patients achieving nodal pCR with NET versus NAC were older (median age 70 versus 50,P=0.004) and had higher progesterone receptor (PR) expression (85% versus 13%,P=0.031), respectively. Of patients not candidates for BCS due to a large tumor relative to breast size, 36/47 (77%) became BCS-eligible with NET (median PR expression 55% versus 5% in those remaining ineligible,P<0.05).Terms of use and reuse: academic research for non-commercial purposes, see here for full terms. https://www.springer.com/aamterms-v1

The Present and Future of Neoadjuvant Endocrine Therapy for Breast Cancer Treatment

“…In those studies with a treatment duration of more than three months, BCS likelihood can range between 40–80% when using aromatase inhibitors [ 22 , 23 ]. According to Montagna et al [ 24 ], up to 77% of noneligible BCS patients were candidates for breast preservation after NET, although this rate was lower in those with low PR expression.…”

“…Unfortunately, although axillary-positive patients have been included in most NET trials, very little has been concluded regarding changes brought about by endocrine treatment at this level. Most authors find that NET is less likely to de-escalate surgery in the axilla than in the breast, even though pCR rates range from 1.3% to 11% [ 24 , 30 ]. A slight increase in these rates was observed by Rusz et al, reaching 13% node pCR in N+ patients after one year of NET with letrozole [ 31 ].…”

“…As reported by other authors, lobular breast cancer had a significantly lower percentage of nodal pCR when compared to ductal histologies (12.4% vs. 15.26%, p < 0.05) [ 32 , 33 ]. Longer treatment duration (>6 months) seems to increase the likelihood of nodal pCR [ 24 , 31 ].…”

Breast cancer neoadjuvant endocrine therapy and COVID-19: a renewed breath with future perspectives

“…10,11 A recent study comparing NET versus NCT found 11% of nodal pCR in previous node-positive breast cancer treated with NET (not statistically different from NCT group), and 77% woman became eligible for breast conserving surgery (BCS). 12 NET is more likely to be successful in de-escalating breast surgery than axillary surgery, because pathologic complete response is not necessary to allow downstaging to BCS, but it is required to avoid axillary lymph node dissection after neoadjuvant treatments. 12 NET is usually limited to the treatment of elderly postmenopausal women with large tumors, who were the worst candidates for NCT or upfront surgery.…”

“…12 NET is more likely to be successful in de-escalating breast surgery than axillary surgery, because pathologic complete response is not necessary to allow downstaging to BCS, but it is required to avoid axillary lymph node dissection after neoadjuvant treatments. 12 NET is usually limited to the treatment of elderly postmenopausal women with large tumors, who were the worst candidates for NCT or upfront surgery. An examination of the United States National Cancer Data Base reveals that only 3% of potentially eligible patients received NET.…”