A study that included more than 20,000 women with stage IV breast cancer finds that survival has improved and is increasingly of prolonged duration, particularly for some women undergoing initial breast surgery, according to the report published online by JAMA Surgery.

Breast cancer is the most common malignancy in women in the United States and the developed world.

Approximately 5 percent to 10 percent of women diagnosed as having breast cancer present with stage IV disease and have an intact primary breast tumour.

While this represents a small portion of patients with breast cancer, given the prevalence of the disease, management of the primary tumour in stage IV disease remains a common clinical scenario.

The appropriate local management of the primary tumour in stage IV breast cancer, which currently is largely considered incurable, continues to be debated, according to background information in the article.

Mary C. Schroeder, Ph.D., of the University of Iowa, Iowa City, and colleagues used data from the Surveillance, Epidemiology, and End Results (SEER) program to evaluate the patterns of receipt of initial breast surgery for female patients with stage IV breast cancer in the United States.

The study included female patients diagnosed between 1988 and 2011 and who did not receive radiation therapy as part of the first course of treatment (n = 21,372).

The researchers analysed the differences in survival, particularly survival of at least 10 years, by receipt of initial surgery to the primary tumour.

Among the study population, the median survival increased from 20 months (1988-1991) to 26 months (2007-2011).

During this time, the rate of surgery declined.

Receipt of surgery was associated with improved survival.

For women diagnosed as having cancer before 2002 (n = 7,504), survival of at least 10 years was seen in 9.6 percent (n = 353) and 2.9 percent (n = 107) of those who did and did not receive surgery, respectively.

Clinical factors that correlated with prolonged survival included surgery, tumour size, hormone receptor status, marital status, and year of diagnosis.

"This work will add to the body of evidence on these important concepts in the care of women with advanced breast cancer. Randomised clinical trials and prospectively enrolled registries will be essential to understanding the underlying causal relationship between our observed association of receipt of surgery and improved survival. A large benefit for many women with stage IV breast cancer with surgery to the intact primary tumour is unlikely, especially as an ever-increasing array of more potent and targeted drugs may be able to provide better control or even eradication of systemic disease," the authors write.

"However, systemic therapies cannot yet manage all macroscopic [large enough to be seen with the naked eye] disease fully. Hopefully, this time will come. Until then, local therapy with surgery to the primary tumour may offer critical disease control for select patients and could be an essential component of prolonged survival."

"While this study's overarching focus is indeed meaningful, it is also informative to place results from this report in the context of conversations regarding breast cancer disparities associated with racial/ethnic identity, young age, and country of origin," writes Lisa A. Newman, M.D., M.P.H., formerly of the University of Michigan, Ann Arbor, in an accompanying commentary.

Lifetime incidence of breast cancer is lower for African American compared with white American women; therefore, African American women account for a smaller proportion of breast cancer cases compared with their general population distribution.

"Thomas and colleagues found a disproportionately high prevalence of African American women among their stage IV study population, and African American women were also 30 percent less likely to undergo surgery. This treatment imbalance raises questions regarding selection of patients that are triaged toward more aggressive care."

Dr. Newman adds that breast cancer incidence increases with age; however, the breast cancer burden of young/premenopausal women generates substantial attention because of the associated impact on a population subset that assumes much of the nation's family and general workforce responsibilities.

"Furthermore, while the population-based incidence rates of breast cancer in women younger than 45 years have been stable over the past several decades, we are indeed seeing a larger number of young patients with breast cancer because census data confirm that this demographic has grown by nearly 10 million since 1980."

"Unfortunately, the population-based incidence of stage IV breast cancer has doubled among young American women but happily, Thomas et al found that younger women were more likely to undergo surgery, and age younger than 45 years was an independent predictor of prolonged survival."

Source: The Jama Network Journals