Greater Radiation Levels May Not Improve Outcomes in Prostate Cancer

While PSA levels decreased in patients, overall survival did not improve in patients with non-metastatic prostate cancer.

Increased radiation may not improve long-term outcomes for patients with non-metastatic prostate cancer, according to a recent study.

New technology has given physicians the ability to administer higher doses of radiation with fewer side effects. However, a study published in the American Journal of Clinical Oncology revealed that this may have little benefit, especially in those with localized prostate cancer.

“In the field of radiation oncology, we often assume that the highest dose that the body can tolerate will be most effective at killing cancer,” said senior study author Robert Den, MD. “Our results argue that this may not be the case, at least not with lower-risk prostate cancer patients.”

During the study, researchers analyzed data from 12 randomized controlled trials of external beam radiations for 6884 non-metastatic prostate cancer patients.

Instead of using the prostate cancer antigen (PSA) test, researchers studied long term outcomes like the development of metastatic cancer and mortality.

The results of the study showed that PSA levels did decrease in patients who received higher doses of radiation, but overall survival and incidence of metastases did not improve.

“It's important to check our assumptions,” said Adam Dicker, chair of Radiation Oncology at the Sidney Kimmel Medical College. “This study suggests that our reliance on the PSA test as a proxy for patient outcomes may not be as useful as many researchers thought, which has broad implications for the design of future clinical trials and the interpretation of current and previous studies.”

Researchers stated that there was no association between increases in radiation doses and worse treatment toxicity. This suggests that the current practices being used are still deemed safe.

“These data suggest that other therapies may be needed with radiation to increase survival,” Den said.