Men with indolent prostate cancer are prescribed radiation therapy more than any other treatment option regardless of tumor biology, according to a study published in the February issue of JAMA Oncology.

Prostate cancer, the most common solid organ cancer among men in the U.S., was responsible for nearly 30,000 deaths nationwide in 2014. Advancements in diagnostic and therapeutic methods, however, have led to earlier diagnosis of mostly indolent cancers and more aggressive, targeted treatments such as radiation therapy and radical prostatectomy. While effective, these treatments are associated with severe adverse consequences that may reduce patient quality of life and life expectancy.

For this study, the research team led by Karim Chamie, MD, of UCLA Medical Center, set out to determine population-based predictors for prostate cancer treatment and how often alternative treatment methods such as watchful waiting or active surveillance were utilized. “With more indolent cancers being diagnosed, active surveillance protocols have been established, with promising oncologic results, and are associated with the greatest quality adjusted life expectancy,” wrote Chamie and colleagues.

The team examined available medical data on 37,621 men diagnosed with prostate cancer between 2004 and 2007 with regular follow up care through Dec. 31, 2009, to determine the prescribed course of treatment: watchful waiting/active surveillance, radiation therapy or radical prostatectomy.

Their results showed that regardless of contributing factors such as age, medical history or tumor biology, radiation therapy was the most commonly prescribed treatment for indolent prostate cancer, utilized in 58 percent of cases. Radical prostatectomy was second at 19 percent, with only 10 percent of patients treated using watchful waiting or active surveillance. “Active surveillance is underused in men with prostate cancer older than 65 years,” Chamie and colleagues wrote. “Aside from age, there is overuse of treatments in men with low-risk disease and clinically significant comorbidities.”

The team also noted that age and comorbidities are more closely correlated with radical prostatectomy, while the use of radiation therapy is often influenced by regional variation and referral patterns.

The high rate of radiation therapy treatment for cases of indolent prostate cancer without consideration of patient demographics and tumor biology is concerning, write Chamie and his colleagues, but efforts to educate and collaborate could help bring reductions in the use of drastic treatments. “Our finding [suggests] that increased use of radiotherapy among patients with indolent disease portends to a collaborative need for increased dissemination of prostate cancer treatment guidelines among our radiation oncology colleagues,” the authors wrote. “Further research into identifying determinants that drive decision-making recommendations for patients diagnosed with low-risk prostate cancer are needed.”