Favorable patient outcomes in this phase II trial conducted by the Radiation Therapy Oncology Group (RTOG) would lead to a larger phase III trial to investigate the treatment strategy’s promising therapeutic benefits
Over the last 10 years, the vast majority of men diagnosed with prostate cancer (an estimated 217,700 in 2010) have an early stage of the disease where the cancer has not spread to lymph nodes or other organs. Considerable research is focused on the best treatment strategy for these patients and recent research indicates that prostate cancer can be effectively treated with hypofractionated radiotherapy which delivers higher doses of radiation in fewer treatments as compared to standard radiotherapy treatment.
Led by principal investigator Himu Lukka, MD (Juravinski Cancer Centre at McMaster University, Hamilton, Ontario), the recently launched RTOG 0938 trial: A Randomized Phase II Trial of Hypofractionated Radiotherapy for Favorable Risk Prostate Cancer will assess quality of life outcomes of two hypofractionated radiotherapy (RT) regimens which have been investigated individually in prior clinical trials. Study participants will be randomized into one of two arms to receive a radiation dose of 36.25 Grays (Gy) administered twice weekly for a total of 5 treatment sessions (7.25 Gy per session) over 15 to17 days (arm 1) or a dose of 51.6 Gy administered in 12 daily treatment sessions (4.3 Gy per session) over 16 to 18 days. The target trial enrollment is 174 participants at RTOG sites across North America.
“While prior studies suggest that hypofractionated RT delivery may produce comparable results to conventional therapy for patients with early stage prostate cancer, it is important to confirm this treatment strategy does not incur more adverse side effects for patients,” says Lukka. “If a hypofractionated regimen is found to produce comparable findings to conventional treatment, it would be more convenient for patients who are now treated over of course of 39 to 41 treatment sessions and would result in substantial health care cost savings.”
To compare health-related side effects between the hypofractionated trial arms and conventional RT treatment, study participants will complete a health-related quality of life (HRQOL) questionnaire (Expanded Prostate Index Composite [EPIC]) at 12 and 24 months and 5 years post-treatment to provide information about their treatment side effects on bowel and bladder function. These data will be compared to those collected with the same EPIC questionnaire from study participants who participated in previously conducted RTOG trial (RTOG 0415) and were randomized to the trial’s conventional arm. “We are fortunate to have the RTOG 0415 benchmark data to determine if either hypofractionation regimen is promising enough for further investigation in a phase III study comparing one or both arms of RTOG 0938 to current standard radiotherapy—which is the study’s goals,” says Lukka.
Study participants will also have the opportunity to participate in companion HRQOL surveys collecting information about the trial’s hypofractionated RT treatment effects on their general health status (using the EQ-5D questionnaire) and on sexual function (using the EPIC questionnaire and Utilization of Sexual Medications/Devices questionnaire). A novel aspect to gathering HRQOL data is the study participants’ option to complete these questionnaires online via the VisionTree Optimal Care website on any computer with Internet access.
The research study also incorporates collection of blood and urine specimens and tumor tissue from study participants who consent to this biomarker trial component. Specifically, the specimen samples will be used to study whether certain genetic markers can identify patients more likely to have adverse effects from radiation treatment. It is hoped this ongoing research will result in improved management of prostate cancer patients’ care.
“This protocol encompasses very important science and has the potential to significantly affect the future treatment of early stage prostate cancer,” says Walter J. Curran, Jr., MD, RTOG Group Chair, and Executive Director of the Winship Cancer Institute of Emory University in Atlanta. “It is one of the first clinical trials to collect tumor tissue from patients receiving hypofractionated radiotherapy for prostate cancer which will aid ongoing research efforts to identify biomarkers to help determine the best treatment options for our patients.”