e18566 Background: We previously elucidated sociodemographic factors associated with risk-of-death, in a subgroup of patients with Stage IV human epidermal growth factor 2 (HER)+ breast cancer. To further understand determinants of disparities in all subgroups of stage IV breast cancer, this study sought to evaluate factors which are predictive of overall survival (OS) in a cohort of patients with metastatic breast cancer (MBC), according to the following subtypes: 1) estrogen receptor (ER)+ or progesterone receptor (PR)+ and (HER)-, (2) (ER+ or PR+) and HER+, (3) (ER- and PR-) and HER-, or (4) (ER- and PR-) and HER+. Methods: Study population included patients with MBC, extracted from the National Cancer Database, treated between 2010 and 2016. Descriptive statistics were used to summarize patient characteristics, and chi-square tests were performed to compare patient characteristics, by ethnic group (white, black, Hispanic, Asian, and other). Multivariate Cox regression models with backward elimination (using significance level of p<0.05) were utilized to compare overall survival among patient cohorts. In addition, Kaplan-Meier survival curves of patient cohort were also produced. Statistics were performed using SAS. Results: Records from n= 47,032 patients were included, the majority were 50 years or older, white, and treated with hormonal therapy. With a median follow-up time of 2.3 years, disparities in OS were observed; black patients were more likely to suffer death (HR=1.12 (1.08-1.16), p<0.0001), compared to white patients. Additional factors contributing to risk of death in MBC included: being male (HR=1.12, (1.02-1.23), p=0.019), having visceral involvement compared to bone only (HR=1.52, (1.05-1.28), p<0.0001), income < $38,000 (HR=1.13 (1.09-1.17), p<0.0001), being on government insurance (HR=1.24, (1.20-1.27), p<0.0001, and having Triple Negative Breast Cancer (ER- and PR-) and HER- status (HR=1.68 (1.60-1.75) p<0.0001). Patients who receive chemotherapy, not hormonal therapy (HR=1.25 (1.2 – 1.3), p<0.0001), were found to have worse prognosis possibly reflecting biology of disease at presentation and lack of specific targeted therapy. Conclusions: This study confirms that sociodemographic disparities exist in OS among patients within the same stage of MBC, and regardless of receptor status subtypes. Clinical practice should focus on closing disparities gaps for those with advanced and MBC, especially among Black, impoverished, and male patients. Better treatment approaches should be sought for patients with visceral metastasis and those diagnosed with triple negative receptor status, who continue to suffer from worse outcomes.
Locoregional therapy targeted at the primary tumour improves overall survival in patients with stage IV metastatic breast cancer: A systematic review and meta-analysis with 185942 patients
