Scott Morgan, MD, FRCPC
A panel of experts has recommended hypofractionated radiation as an alternative to longer, conventional courses of radiation for men with earlystage prostate cancer who opt for external beam radiation therapy (EBRT) instead of other types of treatment or active surveillance.
The new guidelines from the American Society for Radiation Oncology (ASTRO), the American Society of Clinical Oncology (ASCO), and the American Urological Association (AUA) state that moderate hypofractionation confers similar outcomes for prostate cancer control, similar rates of late toxicity, and only a slight increase in acute gastrointestinal toxicity compared with conventional fractionation. This applies to low-, intermediate-, and high-risk groups, although the panelists noted that evidence beyond 5 years of patient treatment history is scant (Table
Moderate hypofractionation was defined as 240 to 340 cGy per fraction compared with conventional fractionated EBRT of 180 to 200 cGy per fraction. The largest evidentiary base for treatment with moderate hypofractionation covered regimens of 6000 cGy delivered in 20 fractions of 300 cGy and 7000 cGy delivered in 28 fractions of 250 cGy, according to the guidelines.
The updated expert guidelines also state that ultrahypofractionation, an even shorter course of radiation, of 3500 to 3625 cGy in 5 fractions of 700 to 725 cGy, may be offered to patients in the low- to intermediate-risk range with prostate sizes less than 100 cm3; however, the recommendation is conditional, based on moderate quality of evidence and lower consensus among the panelists.
“Men who opt to receive hypofractionated radiation therapy will be able to receive a shorter course of treatment, which is a welcomed benefit to many men,” Scott Morgan, MD, FRCPC, assistant professor in the Division of Radiation Oncology at the University of Ottawa, Canada, and co-chair of the guideline panel, said in a release.2
“When clinicians can reduce overall treatment time while maintaining outcomes, it’s to our patients’ benefit, as they can spend less time away from family and less time traveling to and from treatment.”
The 16-member expert panel reviewed data published from December 2001 through March 2017, including findings from 4 large, prospective, randomized clinical trials involving more than 6000 patients. The Society of Urologic Oncology, the European Society for Radiotherapy and Oncology, and the Royal Australian and New Zealand College of Radiologists have also endorsed the guidelines.
This is the first time ASTRO, ASCO, and AUA have issued a joint guideline regarding short-course radiation regimens. Results from several trials including CHHiP, PROFIT, and RTOG-0415 have shown that hypofractionation is a viable alternative to longer, conventional courses of radiation in terms of cancer control, toxicity, and quality of life.
“Conclusive evidence from several large, well-designed randomized trials now confirms that dose escalation can almost universally benefit men with early-stage prostate cancer who choose to manage their disease with external radiation,” Howard M. Sandler, MD, chair and professor of radiation oncology at Cedars-Sinai Medical Center, Los Angeles, California, and cochair of the guideline panel, said in the press release.2
“Significant advances in treatment planning and delivery have enabled oncologists to deliver more powerful, lifesaving doses of radiation in fewer visits and without compromising quality of life,” he added.
The expert panel states that physicians should offer moderate hypofractionation instead of conventional fractionation regardless of patient age, comorbidity, anatomy, and baseline urinary function. That recommendation includes patients with low- or intermediate-risk disease receiving EBRT to the prostate with or without radiation to the seminal vesicles and men with high-risk disease receiving EBRT to the prostate but not the pelvic lymph nodes.
However, experts advise that physicians should make sure patients are aware that there is limited follow-up beyond 5 years in the trials supporting these recommendations. Furthermore, moderate hypofractionation is associated with a small increased risk of acute gastrointestinal toxicity.
The recommendations support a hypofractionation schedule of 6000 cGy delivered in 20 fractions over 4 weeks or 7000 cGy in 28 fractions over 5.6 weeks. The strongest evidence supports 6000 cGy in 20 fractions of 300 cGy because this regimen was used in 2 different randomized trials and was tested in all risk groups, in both the presence and absence of androgen deprivation therapy.