IMRT reduces gastrointestinal complications in prostate cancer patients

Prostate cancer patients who receive intensity modulated radiation therapy (IMRT) are less apt to suffer serious gastrointestinal complications following their treatment than those who receive three-dimensional conformal radiotherapy (CRT), according to new research from the University of Pennsylvania School of Medicine. The study, which will be presented Nov. 1 at the 52nd Annual Meeting of the American Society for Radiation Oncology (ASTRO) in San Diego, found that men who were treated with IMRT had fewer serious bowel complications, including painful rectal inflammation and bleeding (3.5 percent), compared to those who received CRT (4.5 percent).

"While radiotherapy is highly effective in treating prostate cancer, men may live with gastrointestinal, urinary and sexual side effects of treatment for many years. Minimizing these side effects and improving men's quality of life after prostate cancer treatment is incredibly important," says Justin Bekelman, MD, lead author of the study and an assistant professor of Radiation Oncology at the University of Pennsylvania School of Medicine. "Our study offers important evidence to patients and their doctors that IMRT is associated with fewer gastrointestinal problems after treatment."

CRT, the conventional form of radiation therapy, uses imaging studies including CT, MRI and PET scans to map the size, shape and location of tumors and the other organs in the area. IMRT is a more advanced version of CRT, offering a more targeted dose of radiation to the cancerous prostate gland. Since both forms of radiation pass all the way through the body after attacking their target, healthy tissue in the rectum and bladder may be damaged by the radiation beam, causing side effects during and after treatment. Though Medicare and private insurers typically cover both IMRT and CRT, little research has been conducted to show which treatment is associated with less side effects - an important consideration for men choosing among the various treatment options for the disease, which include observation, radiation, surgery, chemotherapy and hormonal therapies.

Using a Medicare database of men across the United States, Bekelman's team studied 12,598 men 65 years and older who were diagnosed with non-metastatic prostate cancer between 2002 and 2004. The authors followed the patients through 2006 and identified complications that were serious enough to require invasive procedures (including surgeries) and/or hospitalization. The findings revealed that among men who received IMRT, 18.8 percent had serious bowel complications during the two years after their treatment, compared to 22.5 percent of men treated with CRT. (Since specifics about each patient's case could not be accounted for in the database, the authors note that some of the complications identified may have been caused by factors other than radiation treatment.) The researchers found no substantial difference in incidence of urinary or sexual side effects such as erectile dysfunction, but Bekelman notes that since the study was limited to complications involving invasive surgical procedures, it may not capture the true prevalence of sexual side effects following treatment, for which patients may have sought less invasive remedies.