Side effects beset prostate therapy

A warning to men considering a pricey new treatment for prostate cancer called proton therapy: Research suggests it might have more side effects than traditional radiation does.

A study of Medicare records found that men treated with proton beams later had one-third more bowel problems, such as bleeding and blockages, than similar men given conventional radiation.

This is an observational study so it is not definitive, but it is one of the largest to compare these treatments. Proton therapy is rapidly growing in use – Medicare covers it – even though no rigorous studies have tested whether it is as safe or effective as usual care.

It costs around $48,000 – at least twice as much as other prostate radiation treatments. Hospitals are rushing to build proton centers, and nine are operating now – sites include Boston, Chicago, Houston, Philadelphia, Jacksonville, Fla., and Loma Linda, Calif., east of Los Angeles. Promoters often claim it is less likely to cause complications.

“There’s no clear evidence that proton therapy is better” for prostate cancer, and the new results suggest it may cause more complications, said Dr. Ronald Chen, a radiation specialist at the University of North Carolina, Chapel Hill.

He led the study and will give results at a medical meeting in San Francisco later this week. They were discussed Tuesday in a telephone news conference sponsored by the American Society of Clinical Oncology and two other cancer groups.

Proton therapy uses proton particles instead of X-rays. In theory, it targets radiation more directly to tumors and spares healthy tissue, which should lead to fewer side effects.