Survival in stage IV breast cancer is improving, notably so in some patients treated initially with surgery, according to a study published in JAMA Surgery.1
“Since this was last looked at extensively, there have been significant advances in cancer care, including systemic therapies, radiation therapy, and imaging modalities. We wanted to better understand the role of surgery in stage IV breast cancer in a contemporary dataset,” Alexandra Thomas, MD, of the Division of Hematology, Oncology, and Blood and Marrow Transplantation at the University of Iowa Carver College of Medicine in Iowa City, wrote in an email to Cancer Therapy Advisor.
“We saw improved survival associated with receipt of surgery in this observational dataset, as others have also found,” she explained. “There is always the possibility of selection bias confounding our results. Results from randomized trials will hopefully provide a clearer answer in this regard. Importantly, we did see that surgery, again in our observational dataset, was associated with prolonged survival of at least 10 years and that this was in women diagnosed in 2002 and earlier. Might this be even better for women diagnosed in 2015 who are receiving ever-better therapies?”
According to the article, 5% to 10% of patients with breast cancer present initially with stage IV disease. Because stage IV breast cancer is viewed as mostly incurable, in addition to its heterogeneous nature, how to manage the primary tumor is debated. Furthermore, the authors pointed out that with today’s modern imaging, women with stage IV breast cancer tended to have lower disease burden, which may affect survival outcomes.
Thomas and colleagues wanted to understand the outcomes for patients with stage IV breast cancer based on surgical treatment of the primary tumor site. Using data from the Surveillance, Epidemiology, and End Results (SEER) Program, they conducted a retrospective cohort study of women diagnosed with stage IV breast cancer between 1988 and 2011 who did not receive radiation in the first course.
The cohort included 21 372 women with 39% (8330 patients) receiving surgery in the initial treatment. Factors noted to be associated with a lower likelihood of receiving surgery included larger tumor size, black race, and hormone receptor (HR)–positive tumors. During the study period, surgical treatment decreased from 67.8% in 1988 to 25.1% in 2011.
Overall, the median survival of the cohort was 23 months. However, those treated with surgery demonstrated a median survival of 28 months compared with 19 months for those without surgery (95% CI, 7.6 – 10.4). Furthermore, women surgically treated for tumors smaller than 2 cm or larger than 5 cm had an increase in survival of 11 months and 7 months, respectively.
The authors noted that median survival improved during the study period. The median survival was 24 months for those who were diagnosed from 1988 to 1991 and received surgery. Median survival increased by 11 months for those diagnosed between 2007 and 2011.
Longer survival was associated with white race or other ethnicities, HR-positive status, marriage during diagnosis, more recent diagnosis, younger age, and smaller tumors. Likewise, surgical treatment was associated with improved survival in multivariate analysis after controlling for clinical and patient characteristics (hazard ratio, 0.60; 95% CI, 0.57 – 0.63).