Wednesday, December 2, 2015

A University of Iowa study that included more than 21,000 women with stage IV breast cancer finds that survival has improved over the past two and a half decades and is increasingly of prolonged duration, particularly for some women undergoing initial breast surgery. The findings were published online Dec. 2 in the journal JAMA Surgery.

Stage IV breast cancer is generally considered incurable, and treatments focus on controlling symptoms and improving length and quality of life. In recent decades, the overall medical view has been that removing the primary tumor will not benefit the patient once the disease has spread throughout the body, but there is evidence that removing primary tumors can prolong survival in some other types of advanced cancer.

Spurred by the observation that a small but growing number of her patients with stage IV breast cancer were living a long time without disease progression, Alexandra Thomas, M.D., professor of internal medicine in the UI Carver College of Medicine and co-leader of Holden Comprehensive Cancer Center's Breast Molecular Oncology Group, teamed up with Mary Schroeder, Ph.D., assistant professor of health services research in the UI College of Pharmacy, to investigate whether receiving surgery to remove primary tumors is associated with improved survival for patients with stage IV breast cancer.

Thomas, Schroeder, and their colleagues used patient data from the Surveillance, Epidemiology, and End Results (SEER) program to study 21,372 female patients diagnosed with stage IV breast cancer between 1988 and 2011 who did not receive radiation therapy as part of their first course of treatment. The researchers analyzed differences in patient survival, particularly survival of at least 10 years, between women who had initial surgery on the primary tumor and women who did not have initial surgery.

Overall, the researchers found that median survival increased from 20 months (in 1988 to 1991) to 26 months (in 2007 to 2011). Although the rate of surgery declined during this time period (from 67.8 percent in 1988 to 25.1 percent in 2011), the study showed that receiving surgery to remove the primary tumor was associated with improved survival. For women diagnosed as having cancer before 2002 (7,504 of the women in the study), survival of at least 10 years was seen in 9.6 percent of those who did receive surgery, compared with 2.9 percent of those who did not receive surgery.

"Our study in this observational data set doesn't suggest that every patient with stage IV breast cancer should undergo surgery, but we showed that for some patients, surgery was associated with prolonged survival," Thomas says.

Although only a small fraction (5 to 10 percent) of women diagnosed with breast cancer are diagnosed with stage IV (advanced) disease and have an intact primary breast tumor, this still represents thousands of women. Thus, understanding which treatments will provide the best outcomes and the most prolonged survival is important.

The UI researchers note that their findings show an association between receiving surgery and improved survival, but more research, including randomized clinical trials and prospectively enrolled registries, will be needed to find out if having surgery is itself a cause of improved survival. Other clinical factors that were also shown to correlate with prolonged survival included smaller tumor size, tumors that express hormone receptors, being married, and being diagnosed more recently. 

In an accompanying commentary in the journal, Lisa A. Newman, M.D., M.P.H., formerly of the University of Michigan, notes that the study also highlights racial disparities in breast cancer rates. Despite the fact that African American women have lower lifetime incidences of breast cancer compared with white American women, the study found a disproportionately high prevalence of African American women among those diagnosed with stage IV cancer. The findings also showed that African American women were 30 percent less likely to undergo surgery than white women and had poorer rates of survival.

With improved imaging technologies and an ever-increasing array of potent, targeted drugs that can control or even eradicate systemic disease, Thomas is optimistic for the future.

"I hope the day will come when targeted systemic therapies can eradicate all disease, but we are not there yet," she says. "However, for a small but growing group of women with stage IV breast cancer, durable remission, or possibly even a cure, might be possible. And today, surgery might still be part of that equation."

In addition to Thomas and Schroeder, the team included Elizabeth Chrischilles, Ph.D., professor of epidemiology and Marvin A. and Rose Lee Pomerantz Chair in the UI College of Public Health, and Seema Khan, M.D., professor of surgery and Bluhm Family Professor of Cancer Research at Northwestern University's Feinberg School of Medicine.

The work was supported in part by the University of Iowa Holden Comprehensive Cancer Center Population Research Core, which is itself partially supported by a National Institutes of Health/National Cancer Institute grant.

Note to editors: This release was adapted from a news release issued by JAMA.