Choosing Wisely? Increased Radiation Does Not Improve Survival Outcomes in Low-Risk Prostate Cancer

Low-risk prostate cancer was the most common type of prostate cancer diagnosed in the United States in 2014, with patients receiving aggressive treatment including radiation or prostatectomy. But is that necessary?

"Our study raises the provocative question of whether radiation dose reduction for patients with low-risk prostate cancer could achieve similar cure rates while avoiding the increased risk of side effects associated with higher radiation doses," said the study's lead author, Anusha Kalbasi, MD, a resident in the department of Radiation Oncology at the Perelman School of Medicine at the University of Pennsylvania.

Along with other researchers at Perelman, Kalbasi initiated a retrospective comparative effectiveness analysis that evaluated the advantage, if any, of dose-escalated external-beam radiation therapy (EBRT) over the standard dose. The data was extracted from the National Cancer Database for patients who had been diagnosed with prostate cancer between 2004 and 2006. The data set, which included more than 42,000 individuals, had 3 risk cohorts: men with low-risk, intermediate-risk, and high-risk prostate cancer and 2 treatment groups: standard dose (68.4 Gy to <75.6 Gy) or dose-escalated (≥75.6 Gy to 90 Gy) EBRT.

The results, published in JAMA Oncology, showed that dose-escalated EBRT improved survival in the intermediate-risk and high-risk patients, but not in the low-risk cohort. In the low-risk group of men, 7-year adjusted survival rates were 86% for both standard-dose and higher-dose patients. In men with a medium-risk, the 7-year adjusted survival rates were 82% and 78% for higher-dose and standard-dose patients, respectively. In the high-risk group, the 7-year adjusted survival rates were 74% and 69% for higher-dose and standard-dose patients respectively.

Their results, the authors concluded, add to the evidence questioning aggressive local treatment strategies in men with low-risk prostate cancer but supporting such treatment in men with greater disease severity.