Radiation still used despite evidence of little benefit to some older breast cancer patients

"We were surprised by these results," said lead author Dr Cary P. Gross, associate professor of internal medicine at Yale School of Medicine. "Clinical trials are considered the gold standard of medical research and in this case the trial was influential enough to lead to a change in treatment guidelines. We expected it to have more of an impact on clinical care at the bedside."

The typical course of treatment for older women with early stage breast cancer is breast-conserving surgery followed by radiation therapy. The purpose of added radiation therapy is to reduce recurrence of the disease. However, many older women have less aggressive tumors that place them at low risk for tumor recurrence.

The Yale team studied the impact of a large research trial funded by The National Cancer Institute (NCI) on clinical practice. Published in 2004, that NCI trial found that radiation therapy had only a small benefit for some women 70 and older with early stage, low-risk breast cancer. As a result of this study, breast cancer treatment guidelines were changed to indicate that radiation therapy could be considered optional for such patients.

But in the years following implementation of the new guidelines, Gross and his colleagues found that there has been minimal impact on the clinical care of older women with breast cancer. The team looked at the use of radiation therapy among Medicare beneficiaries diagnosed with early stage breast cancer before and after the large NCI clinical trial was published. About 79% of women received radiation prior to the study compared with 75% after.

Even among the oldest women (85-94 years), the trial appeared to have little effect on clinician practice: The use of radiation decreased from 37% prior to the study to 33% after.

"These findings have important implications for how the results of clinical research studies are translated into practice," said Gross, who points out that the U.S. government invested over $1 billion in comparative effectiveness research as part of the American Recovery and Reinvestment Act of 2009. "Our societal interest in funding this type of research is appropriate, and the need is great, but we must ensure that the results of such research extend beyond the journal page and are actually incorporated into clinical decision-making."

Other Yale authors on the study include Pamela Soulos, James Yu, Kenneth Roberts, Ann Raldow, Jeph Herrin, and Jessica Long. Gross is a member of Yale Cancer Center.