Prostate Program, Scientific Director's Office, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.Radiation Oncology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
To report the long-term biochemical control of a non-randomized trial comparing standard (STD) and hyper-fractionated (HFX) radiation schedules for prostate cancer treatment.
Between 1993 and 2003, 370 patients entered the study; 330/370 (STD: 179; HFX: 151) were evaluable for current analysis. Median doses were 79.2Gy and 74Gy for HFX (1.2Gy/fr, two daily fractions) and STD (2Gy/fr), respectively; median follow-up was 7.5yr. The two regimens were compared in terms of biochemical relapse-free survival (according to ASTRO definition, bRFS) by univariate (log-rank test) and multivariate analyses (Cox regression hazard model). Based on published relationships between EQD2 and 5-yr biochemical control, α/β values for each subgroup could be estimated.
7.5yr bRFS were 53.4% (±4.4%, 95% CI) and 65.4% (±4.0%) for HFX and STD, respectively (p=0.13); HFX was associated with a poorer outcome in NCCN low+intermediate patients (7.5yr bRFS: 56.6% vs 73.5%, p=0.048) while no differences were seen for high-risk patients (7.5yr bRFS: 44.1% vs 45.3%). Multivariate analysis revealed that NCCN risk grouping (high vs low+intermediate; OR: 0.59, p=0.009) and age (< vs ⩾70yr; OR: 0.67, p=0.03) were the main predictors of worse bRFS. In the subgroups of low+intermediate-risk patients < 70yr, the poorer outcome of HFX was more evident (7.5yr bRFS: 47.1% vs 70.9%, p=0.078) while no difference was seen for older patients (7.5yr bRFS: 69.4% vs 72.0%, p=0.76). Our α/β estimates differ between low+intermediate-risk and high-risk patients.
The bRFS long-term results of this non-randomized trial are consistent with different sensitivities to fractionation depending on NCCN risk grouping. The impact of age on the outcome of HFX for younger low+intermediate patients is consistent with an incomplete repair effect in older patients.
Valdagni R, Nahum AE, Magnani T, Italia C, Lanceni A, Montanaro P, Rancati T, Avuzzi B, Fiorino C. Are you the author?
Reference: Radiother Oncol. 2011 Aug 26. Epub ahead of print.