PHILADELPHIA (October 19, 2015) – Fewer, larger radiation doses did not significantly impact quality-of-life outcomes for prostate cancer patients but may result in potentially worse outcomes for individuals with preexisting urinary problems, according to new research from Fox Chase Cancer Center – Temple Health investigators.
The results of the unprecedented, large-scale, long-term phase III clinical study were presented October 19 at the 57th Annual Meeting of the American Society for Radiation Oncology (ASTRO) in San Antonio, Texas.
“This study is novel because there are currently no long-term data on quality-of-life outcomes in patients receiving hypofractionated radiation therapy,” said study investigator Talha Shaikh, MD, a radiation oncology resident at Fox Chase. “Due to the long life expectancy of these patients, quality-of-life outcomes should be an important consideration when deciding upon treatment options.”
Currently, one of the standard treatment options for patients with localized prostate cancer is radiation therapy. In general, conventional radiation is delivered daily, Monday through Friday, during a roughly eight-week period at 2 gray per fraction. The development of advanced radiation techniques, such as intensity-modulated radiation therapy (IMRT), has made it possible to precisely deliver high doses of radiation to tumors with minimal harm to surrounding tissue.
The delivery of larger, fewer radiation doses has several advantages. For example, the duration of the entire treatment protocol is several weeks shorter, reducing healthcare costs and increasing convenience for patients. Moreover, some research has suggested that hypofractionation may be particularly beneficial for patients with prostate cancer. But until now, the ability of clinicians to make informed decisions about the best course of treatment has been limited, largely due to the absence of prospective data comparing quality-of-life outcomes following conventional versus hypofractionated radiation therapy.
To address this gap in knowledge, Shaikh and his collaborators conducted one of the largest contemporary phase III studies examining moderate hypofractionation in prostate cancer. Between 2002 and 2006, 303 men with low- to high-risk localized prostate cancer received either conventional IMRT (76 gray in 38 fractions at 2 gray per fraction) or hypofractionated IMRT (70.2 gray in 26 fractions at 2.7 gray per fraction). Over an average follow-up period of almost six years, there was no significant difference between the two groups in terms of clinical or treatment-related characteristics or quality-of-life outcomes. However, patients who received hypofractionated radiation were more likely to experience urinary incontinence three to four years after treatment, but this difference was no longer significant by the fifth year.
“These findings may help to select patients who would be potential candidates for hypofractionated radiation therapy,” Shaikh said. “Patients who have poor baseline urinary function may not be good candidates for hypofractionated radiation therapy, whereas patients with good function may tolerate the therapy well.” Researchers at Fox Chase are currently conducting clinical studies to assess whether larger hypofractionation doses could improve clinical and quality-of-life outcomes in patients with prostate cancer.
In the meantime, Shaikh’s research has an important take-home message. “Physicians have often worried about delivering hypofractionated radiation to the prostate due to the surrounding structures and potential for increased toxicity,” Shaikh said. “Our results demonstrate that delivery of hypofractionated radiation is feasible in a select group of individuals. As with any treatment modality, patient selection is a key factor to delivering effective care.”