Radiation after a mastectomy for women with advanced breast cancer saves lives, but almost half of these patients do not receive it.

That is the conclusion of a new study published early online in Cancer, a peer-reviewed journal of the American Cancer Society.

The study's results indicate that treatments that have proven their life-saving potential in clinical trials may not be available to many patients.

After clinical trials in the 1990s revealed the benefits of radiation after mastectomy in advanced breast cancer patients, several major treatment guidelines were published that recommended radiation for these women after their surgery.

To investigate whether these recommendations are being followed, Shervin Shirvani, MD, and Benjamin Smith, MD, of the MD Anderson Cancer Center in Houston, led a team that analyzed information from 38,322 women aged ≥ 66 years treated with mastectomy for invasive breast cancer between 1992 and 2005. (The researchers obtained data from the Surveillance, Epidemiology, and End Results [SEER]-Medicare database, which links cancer registry data to a master file of Medicare enrollment.)

While radiation use increased from 36.5 percent to 57.7 percent between 1996 and 1998 with the publication of landmark clinical trials, no further increase in use was observed between 1999 and 2005 despite the publication of multiple guidelines endorsing it. During this period, only approximately 55 percent of older high-risk breast cancer patients who should have undergone radiation actually received it. According to Dr. Smith, because the percentage of women treated with radiation did not increase after treatment guidelines were published, it seems that these guidelines were not able to improve the quality of care that breast cancer patients received.

"When physicians are not guided by published evidence, there is the chance that patient outcomes will suffer or that patients will undergo unnecessary treatments and tests," said Dr. Shirvani. "Furthermore, beyond the potential for distress and injury to the individual patient, there is also the strong likelihood that medical resources will be wasted on unproven or ineffective treatments." The findings indicate that greater efforts are needed to ensure that what's learned from clinical trials actually affects care in the community.

Article: "Impact of evidence-based clinical guidelines on the adoption of postmastectomy radiation in older women." Shervin M. Shirvani, I-Wen Pan, Thomas A. Buchholz, Ya-Chen Tina Shih, Karen E. Hoffman, Sharon H. Giordano, and Benjamin D. Smith. CANCER; Published Online: June 27, 2011 (DOI: 10.1002/cncr.26081).