As reported in the Journal of Clinical Oncology by Avkshtol et al, the 10-year update of a single-center trial has confirmed the primary analysis of the study, showing no superiority in 5-year biochemical and/or clinical disease failure rate with moderate hypofractionated intensity-modulated radiation therapy (H-IMRT) vs conventionally fractionated IMRT (C-IMRT) in patients with localized prostate cancer.
Study Details
In the trial, 303 men with protocol-defined intermediate- and high-risk prostate adenocarcinoma were randomly assigned to receive C-IMRT at 76 Gy in 38 fractions (n = 152) or H-IMRT at 70.2 Gy in 26 fractions (n = 151). Patients with high-risk disease were prescribed 24 months of androgen-deprivation therapy (ADT) and underwent lymph node irradiation; those with intermediate-risk disease were prescribed 4 months of ADT at physician’s discretion. The primary endpoint was cumulative incidence of biochemical and/or clinical disease failure.
KEY POINTS
- The 10-year cumulative incidence of biochemical or clinical disease failure was 25.9% in the C-IMRT group vs 30.6% in the H-IMRT group.
- No significant differences between groups were observed for biochemical failure, local recurrence, all-cause mortality, or prostate cancer–specific mortality.
Long-Term Outcomes
The median follow-up for the current analysis was 122.9 months. On the basis of updated National Comprehensive Cancer Network risk classification, 28 patients (9.2%) had low-risk, 189 had (62.4%) intermediate-risk, and 86 had (28.4%) high-risk disease. There was no significant difference in either short-term or long-term median ADT use between groups.
The 10-year cumulative incidence of biochemical and/or clinical disease failure was 25.9% in the C-IMRT group vs 30.6% in the H-IMRT group (hazard ratio = 1.31, 95% confidence interval [CI] =0.82–2.11). The 10-year cumulative incidence of distant metastasis was higher in the H-IMRT group (14.3% vs 6.4%, difference = 7.8%, 95% CI = 0.7%–15.1%). No significant differences between the C-IMRT group vs the H-IMRT group were observed in 10-year cumulative incidence of biochemical failure (21.1% vs 25.4%, P = .26), local recurrence (4.7% vs 4.0%, P = .82), all-cause mortality (24.4% vs 33.2%, P = .12), or prostate cancer–specific mortality (4.4% vs 4.4%, P = .89). Cause of death was not known for 31.9% of patients who died.
The investigators concluded, “H-IMRT failed to demonstrate superiority compared with C-IMRT in long-term disease outcomes.”
Eric M. Horwitz, MD, of the Department of Radiation Oncology, Fox Chase Cancer Center, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by the National Cancer Institute and by a grant from Varian Medical Systems. For full disclosures of the study authors, visit ascopubs.org.
