Targeted Radiotherapy Minimizes Side Effects of Prostate Cancer Treatment

Men with prostate cancer treated with intensity-modulated radiation therapy (IMRT) have fewer gastrointestinal complications compared to patients treated with conventional three-dimensional conformal radiotherapy (3D-CRT), according to recent findings.

The study's findings were presented November 1, 2010, at the 52nd annual meeting of the American Society for Radiation Oncology (ASTRO), held in San Diego, CA, USA. "With survivors living many years after treatment, it is very important to minimize gastrointestinal and urinary side effects to allow patients to live a full life after treatment,” Justin Bekelman, M.D., lead author of the study and a radiation oncologist at the University of Pennsylvania (Philadelphia, PA, USA), said. "We specifically looked at IMRT, given its potential to minimize radiation side effects and its higher cost compared to other treatments. Our study shows there is a benefit for men with prostate cancer to receive IMRT over conventional treatment in terms of gastrointestinal side effects. But there is no difference between the two treatments in terms of urinary side effects.”

IMRT and 3D-CRT are dedicated types of external beam radiation therapy where radiation is directed through the skin to the cancer and the immediate surrounding area to destroy the tumor and any stray cancer cells. Treatments are painless, similar to receiving an X-ray.

Policymakers and clinicians have highlighted the need for comparative studies of prostate cancer treatments. However, there is little evidence comparing IMRT to traditional radiation therapy. 3D-CRT, uses computers and special imaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI), or positron emission tomography (PET) scans to show the size, shape, and location of the tumor and surrounding organs. Because the radiation beams are very precisely directed, neighboring normal tissue receives less radiation.

IMRT is a specialized form of 3D-CRT that better shapes the radiation to the tumor. With IMRT, it may be possible to limit further the amount of radiation received by healthy tissue near the tumor.

This study used the Surveillance, Epidemiology and End Results (SEER)-Medicare database to compare the gastrointestinal and urinary complications of men 65 years or older with prostate cancer within two years of treatment with IMRT or 3D-CRT. The researchers specifically assessed common gastrointestinal side effects like inflammation of the rectum lining (proctitis) and rectal bleeding, along with the urinary side effects like inflammation of the bladder tissue (cystitis) and blood in the urine (hematuria).

The demonstrated that IMRT was associated with a modest reduction in gastrointestinal complications associated with radiation, including proctitis and rectal bleeding. Urinary complications, such as cystitis and hematuria, did not significantly differ between the groups.

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