Radiating Prostate Cancer

Prostate cancer treatment with IMRT compared to proton therapy examined

/ Author:  / Reviewed by: Joseph V. Madia, MD

(RxWiki News) Between proton therapy, intensity-modulated radiation therapy (IMRT) and the older conformal radiation therapy, the three types of external radiation therapies used to treat prostate cancer differ slightly.

A recent study weighs the pros and cons of each.

A comparison of the overall effectiveness of radiation therapies used in prostate cancer treatment looked at proton therapy, IMRT, and conformal radiation, publishing statistics on remission and side effects.

No radiation treatment was without side effects, but overall IMRT looks hard to beat.

"Ask your oncologist which radiation therapy is right for you."

Proton therapy uses larger, slower alpha particles, and the other two treatments use higher energy ionizing radiation. Proton therapy is theorized to limit damage to cells around the tumor as the radiation damage is more localized.

IMRT is a modified version of the older conformal radiation radiation therapy technology, and both are forms of external ionizing radiation with high energy X ray, or gamma waves. IMRT showed a clear performance improvement against conformal radiation.

Analysis from the study's authors showed that although proton therapy was receiving increased amounts of funding and acclaim, results did not bear out the hype. Gastrointestinal problems, which can be significant and include loss of bowel control, were higher in patients who had undergone proton therapy.

Proton therapy is a newer technology and cost reflects that. However, the study authors concluded that the evidence did not suggest an improvement over IMRT at this time, but further development of the technology may change that.

Between the two forms of ionizing radiation, IMRT seemed to be the best treatment over conformal radiation, as cancer recurrence was 20 percent less, yet IMRT had higher rates of erectile dysfunction than was observed in treatment with conformal radiation.

The use of IMRT in the last decade has gone from a tiny fraction of all treatment at 0.15 percent to the majority of radiation treatment at 96 percent.

Study author Ronald Chen, MD, wrote, "Proton therapy is a high-profile, high-cost prostate cancer treatment. Since 2007, multiple proton facilities have been built, and direct-to-consumer advertising is likely to lead to a substantial increase in use."

The research paper concluded with the findings that, "Overall, our results do not clearly demonstrate a clinical benefit to support the recent increase in proton therapy use for prostate cancer."

Brachytherapy, or the use of internal radiation to treat prostate cancer, has had several very favorable studies when compared to external radiation, but was not included in this comparison.

The retrospective analysis was performed on records from patients with localized prostate cancer, 12,976 in total, taken from the National Cancer Institute's database on cancer statistics, the Surveillance Epidemiology and End Results (SEER) project from the year 2000 to 2009.

Results from the study were published in the Journal of the American Medical Association online April 17, 2012.

This research was funded by the Agency for Healthcare Research and Quality, U.S. Department of Health and Human Services, as well as a grant from the NIH. Other financial relationships were not made publicly available.

Reviewed by: 
Review Date: 
April 25, 2012
Last Updated:
April 26, 2012