Importance: Management of the primary tumor site in patients with metastatic breast cancer remains controversial.
Objective: To evaluate the patterns of receipt of initial breast surgery for female patients with stage IV breast cancer in the United States, with particular attention to women who survived at least 10 years.
Design, setting, and participants: A retrospective cohort study using data from the Surveillance, Epidemiology, and End Results (SEER) program. Female patients diagnosed as having stage IV breast cancer between 1988 and 2011 and who did not receive radiation therapy as part of the first course of treatment were included (N = 21 372). Kaplan-Meier estimates of median survival and descriptive statistics were used to compare patient and tumor characteristics by receipt of breast surgery at diagnosis. A Royston-Parmar survival model and logistic regression analysis assessed demographic and clinical factors associated with survival and prolonged survival (of at least 10 years).
Main outcomes and measures: Differences in survival, particularly survival of at least 10 years, by receipt of initial surgery to the primary tumor.
Results: Among the 21 372 patients, the median survival increased from 20 months (1988-1991) to 26 months (2007-2011). During this time, the rate of surgery declined (odds ratio [OR], 0.16; 95% CI, 0.12-0.21). Even so, receipt of surgery was associated with improved survival in multivariate analysis, which controlled for patient and clinical characteristics, along with time period (hazard ratio, 0.60; 95% CI, 0.57-0.63). For women diagnosed as having cancer before 2002 (n = 7504), survival of at least 10 years was seen in 9.6% (n = 353) and 2.9% (n = 107) of those who did and did not receive surgery, respectively (OR, 3.61; 95% CI, 2.89-4.50). In multivariate analysis, survival of at least 10 years was associated with receipt of surgery (odds ratio, 2.80; 95% CI, 2.08-3.77), hormone receptor-positive disease (OR, 1.76; 95% CI, 1.25-2.48), older age (OR, 0.41; 95% CI, 0.32-0.54), larger tumor size (OR, 0.37; 95% CI, 0.27-0.51), marital status of being separated at the time of diagnosis (OR, 0.67; 95% CI, 0.51-0.88), and more recent year of diagnosis (OR, 1.43; 95% CI, 1.02-1.99).
Conclusions and relevance: Survival in stage IV breast cancer has improved and is increasingly of prolonged duration, particularly for some women undergoing initial breast surgery. As systemic therapy advances provide better control of distant disease in stage IV breast cancer, and as women present with lower distant disease burdens, these findings on initial surgery to the primary tumor may be of importance.