As reported in The Lancet Oncology by Nilsson et al, the 10-year analysis of the phase III HYPO-RT-PC trial confirmed the noninferiority of ultra-hypofractionated vs conventionally fractionated radiotherapy (RT) in failure-free survival in patients with localized prostate cancer.
The previously reported primary analysis of the trial showed noninferiority of the ultra-hypofractionated group vs the conventional group in failure-free survival.
Study Details
In the open-label trial, 1,180 patients with intermediate- or high-risk disease (per-protocol population) from sites in Sweden and Denmark were randomly assigned between July 2005 and November 2015 to receive: ultra-hypofractionated RT (n = 589) at 42.7 Gy in 7 fractions, 3 days per week for 2.5 weeks; or conventionally fractionated RT (n = 591) at 78.0 Gy in 39 fractions, 5 days per week for 8 weeks. Patients had received no androgen-deprivation therapy. The primary endpoint was failure-free survival, defined as time from randomization to first occurrence of biochemical failure, evidence of clinical progression, initiation of androgen-deprivation therapy, or death from prostate cancer, analyzed in the per-protocol population.
Key Findings
After a median follow-up of 10.7 years (interquartile range [IQR] = 9.1–12.7 years) in the ultra-hypofractionation group and 10.6 years (IQR = 9.0–13.0 years) in the conventional group, 178 vs 205 failure-free survival events were observed. Failure-free survival at 10 years was 72% (95% confidence interval [CI] = 68%–76%) in the ultra-hypofractionated group vs 65% (95% CI = 61%–69%) in the conventional group; the adjusted hazard ratio (HR) was 0.84, 95% CI = 0.69–1.03, confirming noninferiority.
The 10-year cumulative incidence of late grade ≥ 2 genitourinary toxicity was 30% (95% CI = 26%–34%) in the conventional group vs 28% (95% CI = 24%–32%) in the ultra-hypofractionated group (HR = 1.01, 95% CI = 0.81–1.25, P = .95). Late grade ≥ 2 gastrointestinal toxic effects occurred in 14% (95% CI = 11%–18%) of the conventional group vs 14% (95% CI = 11%–17%) of the ultra-hypofractionated group (HR = 0.94, 95% CI = 0.70–1.28, P = .72).
The investigators concluded: “This 10-year follow-up confirms the non-inferiority of the ultra-hypofractionated radiotherapy regimen compared with the conventionally fractionated, with similar toxicity profiles. The findings support the seven-fraction schedule as a safe, effective, and practical standard-of-care option for patients with intermediate-risk prostate cancer.”
Per Nilsson, PhD, of Radiation Physics, Department of Haematology, Oncology and Radiation Physics, Skåne University Hospital, Lund, Sweden, is the corresponding author for The Lancet Oncology article.
DISCLOSURE: The study was funded by The Nordic Cancer Union, Swedish Cancer Society, Swedish Research Council, and others. For full disclosures of the study authors, visit thelancet.com.
