Shortened RT schedule has similar efficacy as conventional RT schedule in low-risk prostate cancer patients

Of the more than 220,000 patients newly diagnosed with prostate cancer in 2015, the vast majority will have had early-stage disease at low risk for recurrence. A clinical trial published online April 4th in the Journal of Clinical Oncology confirms that these patients can be treated with a shortened (or hypofractionated) course of radiotherapy (70 Gy of radiation delivered in 28 fractions over 5.6 weeks) and experience a similar level of cancer control as those treated with a conventional course of radiotherapy (73.8 Gy of radiation delivered in 41 fractions over 8.2 weeks). Coordinated by the Radiation Therapy Oncology Group (RTOG), now conducting research as NRG Oncology, RTOG 0415 analyzed data from 1,092 men diagnosed with low-risk prostate cancer who were randomly assigned to either a conventional schedule lasting more than 8 weeks (542 men) or a hypofractionated schedule (550 men).

"Given the potential to increase patient convenience and reduce treatment costs, we set out to determine if the efficacy of this approach is no worse than that of a conventional schedule in men with low-risk prostate cancer," says the trial's principal investigator, W. Robert Lee, M.D., M.Ed., M.S., a radiation oncologist at Duke University. Lee points out that, from a curative perspective, the study results should make practitioners feel comfortable that the shorter radiotherapy course is as effective as a conventional course. "The study results are directly analogous to the breast cancer story in which shorter courses of radiotherapy work as well," says Lee.

While treatment efficacy was similar, men treated with the shorter regimen were reported to experience more mild side effects (grade 2), but more severe, late grade 3 gastrointestinal (GI) and genitourinary (GU) side effects were not different between the two treatment schedules. (GI, 4.1 percent [70 Gy] vs. 2.4 percent [73.8 Gy]; GU 3.5 percent [70 Gy] vs. 2.1 percent [73.8 Gy], respectively). Lee emphasizes that these toxicities are physician-reported results, which do not always reflect the patients' experiences accurately. To answer the important question regarding what patients thought about their treatment side effects, the investigators will analyze patient-reported quality of life data and anticipate reporting these results later this year. Lee continued, "The good news is that very soon we will have patient-reported outcomes to compare the patients experience with the two schedules".

"These results are another example of NRG Oncology's exemplary work in advancing the treatment of men with prostate cancer," says Walter J. Curran, Jr., M.D., an NRG Oncology Group Chairman and Executive Director of the Winship Cancer Institute of Emory University in Atlanta. "Congratulations to the research team and participating sites for enrolling patients and concluding the study ahead of schedule. This performance demonstrates the importance that the radiation oncology community places on learning whether a hypofractionated radiation schedule can both increase patient convenience and save health care resources."