Impact of surgery and radiation of the primary among women with de novo stage IV breast cancer.

Abstract

1032 Background: The aim of this retrospective study was to determine the impact of surgery(S) and radiation(R) therapy to the primary tumor among patients (pts) with stage IV denovo breast cancer. Methods: The SEER registry was used to identify pts with denovo stageIV breast cancer diagnosed between 1988 and 2008. Pts were divided into 4 groups based on type of treatment to primary tumor: both S+R, S alone, R alone, or no treatment of primary (no S/R). Breast cancer specific survival (BCS) was calculated from the date of diagnosis of breast cancer to the date of death from breast cancer or last follow up. Survival outcomes were estimated by the Kaplan-Meier method, and Cox models were fit to determine the association between treatment of primary and survival after adjusting for potential confounders (e.g age, grade, hormone receptor and race). Results: 25903 pts were identified; 4640 (17.9%) S+R, 6556 (25.3%) S, 4467 (17.2%) R, and 10240 (39.5%) no S/R. 1183 (4.6%) had surgery to sites other than the primary. Median age was 63 years. Median follow-up was 14 months. Median BCS was 23 months. Median BCS among pts who underwent S+R, S, R and no S/R was 36 months, 31 months, 18 months and 15 months respectively (p<0.0001). Among pts who underwent S+R, median BCS among pts who did and did not have surgery to sites other than primary was 50 months and 41 months respectively (p=0.029). Of the pts treated with S+R 10-year BCS was 18%. In the multivariable model compared to women who were in the no S/R group those who underwent S (HR= 0.59, 95%CI 0.55- 0.62,p<0.0001) and S+R (HR=0.51, 95%CI 0.47-0.55,p<0.0001) had decreased risk of death from breast cancer and those who underwent R (HR=1.13, 95% CI 1.04-1.21, p=0.002) had an increased risk of death from breast cancer. Pts who had surgery to sites other than the primary tumor had decreased risk of death from breast cancer compared to those who did not (HR=0.80, 95%CI 0.72-0.89,p<0.0001). Conclusions: Our results indicate that S+R of the primary breast tumor among pts with denovo stage IV breast cancer maybe associated with a decreased risk of death from breast cancer. A select subgroup of pts who undergo S+R may also benefit from surgery to sites other than the primary which may afford them maximum survival advantage.