Hypofractionated external beam radiotherapy (EBRT) delivers the total prescribed therapeutic radiation dose in fewer, larger-dose fractions than standard radiotherapy dose schedules, accelerating treatment time.
“The key advantages of moderate hypofractionation, owing to its shorter treatment courses, are lower cost and greater convenience for patients,” said Scott Morgan, MD, assistant professor of radiation oncology at the University of Ottawa in Canada.
Localized prostate cancer is particularly well-suited for hypofractionated radiotherapy because prostate tumors are intrinsically more radiosensitive than other nearby, healthy tissues.1 Larger radiation dose fractions with shorter overall treatment durations should therefore have a better effect on tumors than longer radiotherapy regimens with smaller daily doses, added Ronald C. Chen, MD, MPH, associate professor in the department of radiation at the University of North Carolina (UNC) at Chapel Hill and the UNC Lineberger Comprehensive Cancer Center.
“This idea is the basis for the research on hypofractionation in this disease,” Dr Chen said.
Fewer fractions of at least 2.5 Gy can yield better tumor cell death rates than conventional 1.8 to 2.0 Gy–range conventional radiation-dose schedules — and should do so without increasing toxicity to adjacent healthy, non-target tissues, agreed Thomas Zilli, MD, of Geneva University Hospital in Switzerland.
That expectation has been largely justified for primary radiotherapy.2
“There have been at least 9 randomized trials comparing conventional fractionation (8 to 9 weeks of radiation) vs moderate hypofractionation (4 to 5 weeks of radiation) in prostate cancer,” Dr Chen said. “These trials have essentially shown that moderate hypofractionation is similarly safe and effective as the conventional, much longer treatment courses.”