Studies have consistently demonstrated that conventionally-fractionated high dose external beam radiation therapy, consisting of daily treatment for two months, decreases prostate cancer recurrence and improves metastasis-free survival. Previous studies also demonstrate that moderate hypo-fractionated radiation therapy, consisting of daily treatment for one month using a larger dose per treatment, provides a similar low risk of recurrence. The risk may even be lower with hypo-fractionated radiation therapy than conventionally fractionated high dose external beam radiation therapy.
To test the hypothesis of a lower risk of recurrence with different radiation therapies, investigators at Brigham and Women’s Hospital (BWH) led a systematic review and meta-analysis to assess whether hypo-fractionated radiation therapy demonstrated a lower recurrence risk compared with conventionally-fractionated high dose external beam radiation therapy and to assess the relative impact of these two treatments on bladder and rectal function.
They found that the one-month duration hypo-fractionated radiation was associated with a significant improvement in recurrence compared to the two-month duration conventionally-fractionated high dose external beam radiation and therefore would be reasonable to consider in men with intermediate risk prostate cancer who do not have risk factors that could predispose them to bladder side effects years later.
“Our results provide evidence for clinicians to consider hypo-fractionated radiation as compared with conventionally-fractionated high dose external beam radiation as a preferred radiation treatment in men with intermediate-risk prostate cancer and at low risk of other complications,” says Trevor Royce, MD, MPH, a specialist in the Department of Radiation Oncology at BWH. He notes that the shorter course, with higher doses over fewer days “may be the preferred approach in appropriately selected patients with localized prostate cancer,” due to reduced treatment time and cost to the patient and greater convenience.
Researchers analyzed data from over 5,484 men from three randomized studies comparing both therapies in men with prostate cancer. Of them, 64.8 percent had intermediate-risk prostate cancer. Hypo-fractionated radiation as compared with conventionally-fractionated high dose external beam radiation was associated with a significant 13 percent reduction in the risk of recurrence.
“Late bladder and urethra toxicities were noted to be higher in the hypo-fractionated radiation as compared with conventionally-fractionated high dose external beam radiation group, which necessitates carefully choosing men who are not at risk for sustaining a late bladder or urethral side effect,” says senior author Anthony D’Amico, MD, PhD, chief of Genitourinary Radiation Oncology at BWH. “Men to exclude would be those who get up more than three times at night to urinate, or have urgency to urinate, or incontinence, or men who are on anti-coagulants that could increase the risk of bleeding.”