By Robert Preidt
"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 Dr. Robert Den, a researcher at Thomas Jefferson University's cancer center in Philadelphia.
"Our results argue that this may not be the case, at least not with lower-risk prostate cancer patients," Den added in a university news release.
The researchers reviewed 12 studies that assessed the use of external beam radiation treatment for men with localized prostate cancer. The clinical trials included more than 6,800 patients.
As patients received higher doses of radiation, there was a drop in prostate-specific antigen (PSA) levels, which are used to monitor prostate cancer. However, higher doses of radiation did not lead to lower rates of prostate cancer spreading to other parts of the body or higher survival rates over the long-term.
The study was published online recently in the American Journal of Clinical Oncology.
"It's important to check our assumptions," said Adam Dicker, chair of radiation oncology at the university's medical college.
"This study suggests that our reliance on the PSA test as a proxy for patient outcomes may not as useful as many researchers thought," he said. "This has broad implications for the design of future clinical trials and the interpretation of current and previous studies."