Study Finds Low Risk of Toxicity in Prostate Cancer Patients Treated With Hypofractionated Radiation Therapy

A photo looking over the shoulder of a patient as a masked Fox Chase doctor looks at them, both standing in a medical room.
Dr. Eric M. Horwitz, professor and chair of the Department of Radiation Oncology

PHILADELPHIA (October 25, 2021)—A multi-institutional retrospective analysis conducted by researchers at Fox Chase Cancer Center has found that early stage prostate cancer patients treated with moderately hypofractionated intensity-modulated radiation therapy or proton beam radiation therapy had low risk of serious late genitourinary and gastrointestinal complications.

The study, “Dosimetric Predictors of Toxicity in Patients with Early-Stage Prostate Cancer Treated with Moderately Hypofractionated IMRT or PBT: A Multi-Institutional Analysis,” was presented today during a poster session at the American Society for Radiation Oncology (ASTRO) 2021 Annual Meeting in Chicago.

“This is really the only study that compares moderately hypofractionated intensity-modulated radiation therapy to moderately hypofractionated proton beam treatment,” said Eric M. Horwitz, MD, FABS, FASTRO, an author on the study and chair of the Department of Radiation Oncology at Fox Chase.

“Last year, we compared overall toxicity between the two different groups. This particular study offers a more detailed look at these groups and asks, ‘Are there some factors we can identify that actually predict for side effects,’” he said.

The study population included 1,139 early-stage prostate cancer patients, including 667 treated with intensity-modulated radiation therapy and 472 treated with proton beam therapy. Patients from five referral centers across the United States who were treated from 2002 through 2018 for low- or intermediate-risk prostate adenocarcinoma were included in the study.

“One of the things we’ve always thought was that intensity-modulated radiation therapy tends to have more urinary side effects and proton beam therapy tends to have more gastrointestinal side effects, which is what we saw in this study,” said Horwitz.

This analysis showed that proton beam therapy plans yielded less exposure of non-target organs to lower-dose radiation while intensity-modulated radiation therapy plans yielded less exposure of non-target organs to higher-dose radiation.

“The rates of severe toxicity were actually extremely low no matter what treatment a patient got, which is very important,” said Horwitz. “Probably the most important information patients can take from this study is that moderately hypofractionated intensity-modulated radiation therapy and proton beam therapy are both very safe and effective options. We are also well versed in how to minimize side effects as much as possible, so patients can feel comfortable and confident in receiving either of these treatments.”

Fox Chase Cancer Center (Fox Chase), which includes the Institute for Cancer Research and the American Oncologic Hospital and is a part of Temple Health, is one of the leading comprehensive cancer centers in the United States. Founded in 1904 in Philadelphia as one of the nation’s first cancer hospitals, Fox Chase was also among the first institutions to be designated a National Cancer Institute Comprehensive Cancer Center in 1974. Fox Chase is also one of just 10 members of the Alliance of Dedicated Cancer Centers. Fox Chase researchers have won the highest awards in their fields, including two Nobel Prizes. Fox Chase physicians are also routinely recognized in national rankings, and the Center’s nursing program has received the Magnet recognition for excellence six consecutive times. Today, Fox Chase conducts a broad array of nationally competitive basic, translational, and clinical research, with special programs in cancer prevention, detection, survivorship, and community outreach. It is the policy of Fox Chase Cancer Center that there shall be no exclusion from, or participation in, and no one denied the benefits of, the delivery of quality medical care on the basis of race, ethnicity, religion, sexual orientation, gender, gender identity/expression, disability, age, ancestry, color, national origin, physical ability, level of education, or source of payment.

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