Abstract PD7-06: Trends in surgical resection for stage IV breast cancer: Less surgery more systemic treatment

Abstract Background: There is debate regarding the benefit of breast surgery in women with stage IV breast cancer, especially among those with oligometastatic disease and good response to systemic therapy. Although some retrospective studies have suggested that locoregional therapy may improve survival, this finding has not been universally replicated in randomized controlled trials (RCT) in India, Turkey, and recently the US. To assess need for dissemination of trial results by members of the Alliance/American College of Surgeons Clinical Research Program Dissemination and Implementation (ACS CRP D&I) committee, we sought to determine trends in surgical resection and other therapies for stage IV breast cancer in response to these findings. Methods: The National Cancer Database (NCDB) was queried to identify women diagnosed with clinical stage IV breast cancer of ductal, lobular, or metaplastic histology between 2004-2017. Trends in the rate of women who underwent surgery with breast-conserving surgery (BCS) or mastectomy, radiation, and/or systemic treatments were compared. Possible predictors of breast surgery were examined in univariable and multivariable analysis. Results: We identified 87,331 cases meeting inclusion criteria and assessed demographics for surgery versus no surgery. Of the 87,331 cases, 7,718 (9%) underwent BCS and 17,625 (20%) underwent mastectomy. Rates of breast surgical resection for women with clinically diagnosed stage IV breast cancer rose until 2009, reaching a peak at 37%, followed by a decline to a rate of 18% in 2017 (Table). The largest decline was seen in the hormone receptor positive (HR+) and HER2- subgroup with 71% of patients undergoing surgery in 2007 down to 15% in 2017. Concurrently, the mean number of days between chemotherapy initiation and definitive surgery has been on the rise, ranging from 52 days in 2004 up to 94 days in 2017. In 2004, the rate of systemic therapy alone was slightly more common than locoregional therapy (surgery and/or radiation) with or without systemic therapy (48% vs 37%). By 2017, systemic therapy alone was by far more frequently utilized (69% vs 20%, p<0.001). On multivariable analysis, factors associated with reduced odds of receiving surgery were older age, black race, higher comorbidity index, being uninsured, smaller tumors, lower histologic grade, multiple sites of metastasis, and treatment with chemo-endocrine therapy (all group p values ≤0.001). Factors associated with increased odds of receiving surgery were metaplastic histology, TN subtype, and radiation therapy (all group p values ≤0.001). Conclusions: Rates of surgical resection of the breast primary for stage IV breast cancer have been on the decline in recent years, especially for HR+/HER2- disease, suggesting that providers are responding to the lack of benefit demonstrated in RCTs. Higher rates of surgery in patients with HR-/HER2+ disease and the concurrent rise in the time interval between initiation of systemic therapy and definitive surgical intervention suggest that providers may still be selecting surgery for patients with certain subtypes or those with a durable response to systemic therapy. These areas of continued clinical equipoise could be a target for future studies or de-implementation strategies. OverallHR+/HER2-HER2+TNUnknownSurgery/Total%Surgery/Total%Surgery/Total%Surgery/Total%Surgery/Total%20041189/351334-55-30-50-3420051202/353834-65-35-23-3420061268/375834-54-36-31-3420071571/433636-71-41-32-3620081992/54203754/925926/544820/41491892/52333620092194/592437172/3604883/1525556/106531883/53063520102318/6419361162/331835554/134841352/80144250/9522620112322/6921341220/378932532/144137384/91542186/7762420122238/7110311177/393830587/163536339/85340135/6842020132147/7579281173/423128534/172831334/92536106/6951520142013/8033251086/442825496/185227306/99831125/7551720151805/794323914/434321517/198126288/9962986/6231420161609/819420829/464018459/196823247/10122474/5741320171477/813618722/467815421/190522256/10372578/51615Percent of women with stage IV breast cancer undergoing surgery by year and receptor subtype. Rows containing any number <10 are not reported by subtype to maintain confidentiality, per NCDB guidelines. Citation Format: Sasha R Douglas, Ingrid Lizarraga, Judy C Boughey, Anna Weiss, Kelly Hunt, Diana Dickson-Witmer, Preeti D Subhedar, Ko Un Park, Beiqun Zhao, Sarah Blair. Trends in surgical resection for stage IV breast cancer: Less surgery more systemic treatment [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD7-06.