Nancy Baxter, M.D., Ph.D., associate professor and researcher at the University of Minnesota Medical School and Cancer Center, led the research team that conducted this study. Their findings along with an editorial about the study will be published in the Nov. 23, 2005 issue of the Journal of the American Medical Association (JAMA).
Baxter and her colleagues used Surveillance, Epidemiology and End Results (SEER) registry data, which is kept by the National Cancer Institute (NCI) and linked to Medicare, to review the records of 6,428 women. These women were age 65 and older when diagnosed with pelvic malignancies between 1986 through 1999. The researchers' purpose was to determine whether women who undergo pelvic radiation therapy for pelvic malignancies including cervical, anal, and rectal cancers have a higher rate of pelvic fracture than women with pelvic malignancies who do not receive radiation therapy.
"We found that women who underwent radiation therapy for anal cancer had a three times greater rate of fractures," Baxter says. "Women who had radiation therapy for rectal and cervical cancer had nearly double the rate of fractures.
"We further found that of the 554 women who developed pelvic fractures, 499, or slightly more than 90 percent, were hip fractures," she adds.
The researchers found no significant difference in the rate of arm and spine fractures between women who received pelvic radiation therapy and those who did not.
"Admittedly, the technology used today and the way radiation therapy is given has improved and is better controlled than in the 1980s and 90s," Baxter says. "Nonetheless, our findings point out a concern that women who undergo radiation therapy for pelvic malignancies and their physicians need to be aware of and take precautions to prevent fractures."
She notes that women over age 50 already have about a 17 percent chance of hip fracture in their lifetime because of osteoporosis, or thinning of the bones, that accelerates after menopause. This fact coupled with radiation therapy for pelvic malignancies could put a woman at significant risk for fractures.
Radiation therapy is a common treatment for cervical, anal, and rectal cancer. While it is a proven, effective treatment, Baxter suggests women who have had or are having radiation therapy for pelvic malignancies talk with their physicians about the procedure and follow-up care aimed at preventing factures, including regular checks of the density levels of their bones.
This study was conducted with grants from the Veterans of Foreign Wars and the University of Minnesota Cancer Center. Lead researcher Nancy Baxter, M.D., Ph.D., worked with her University of Minnesota colleagues Beth Virnig, Elizabeth Habermann, and Sara Durham, as well as Joel Tepper, M.D., at the University of North Carolina, to conduct this study.