GU Cancers Symposium 2020: Long-Term Outcomes With Hypofractionated Radiotherapy for Prostate Cancer
Posted: Tuesday, February 18, 2020
The updated results of a noninferiority trial indicated that use of 60 Gy/20 fractions is not inferior to 74 Gy/37 fractions of hypofractionated radiotherapy for localized prostate cancer at 8 years of follow-up. These findings support the continued use of hypofractionated over conventional radiotherapy as the standard of care in this patient population, according to David P. Dearnaley, MD, of The Royal Marsden NHS Foundation trust, who presented these results on behalf of his colleagues at the 2020 Genitourinary (GU) Cancers Symposium in San Francisco.
The CHHiP trial recruited 3,216 men between October 2002 and June 2011 who had node-negative T1–T3a localized prostate cancer and had a risk of seminal vesical involvement of up to 30%. Participants were randomly assigned to receive either 74 Gy/37 fractions, 60 Gy/20 fractions, or 57 Gy/19 fractions. Patients were also started on androgen-deprivation therapy at least 3 months before radiotherapy began and continued it until the end of radiotherapy.
The 8-year time to biochemical failure or clinical failure–free rate was 80.6% in the 74-Gy group, 83.7% in the 60-Gy group, and 78.5% in the 5-7Gy group. Noninferiority of the 60-Gy/fraction treatment was confirmed with a hazard ratio of 0.84, but noninferiority could not be declared in the 57-Gy group, with a hazard ratio of 1.17.
Late toxicity assessed by clinicians was similar across all groups, and late side effects were few across all groups. At 5 years, grade 2 or higher (according to the Radiation Therapy Oncology Group score) bowel toxicity was seen in 1.6%, 2.0%, and 1.9% of men in the 75-Gy, 60-Gy, and 57-Gy groups, respectively. In addition, grade 2 or higher bladder toxicity was seen in 1.9% of men in the 74-Gy group, 1.5% of men in the 60-Gy group, and 1.9% of men in the 57-Gy group.
Disclosure: For full disclosures of the study authors, visit meetinglibrary.asco.org.
