Comparative effectiveness of different radical radiotherapy treatment regimens for prostate cancer: a population-based cohort study
Menée à partir de données suédoises portant sur 15 164 patients atteints d'un cancer de la prostate traité par radiothérapie radicale entre 1998 et 2016, cette étude compare l'efficacité, du point de vue du nombre de décès par cancer de la prostate, de différents protocoles de radiothérapie (radiothérapie externe avec fractionnement standard 2x35Gy ou 2X39 Gy, radiothérapie externe avec hypofractionnement modéré, radiothérapie externe en combinaison avec une curiethérapie à haut débit de dose)
Background : It is unclear which radiotherapy technique and dose fractionation scheme is most effective in decreasing the risk of prostate cancer death. Methods : We conducted a population-based cohort study among 15,164 men in the Prostate Cancer database Sweden (PCBaSe) version 4.0 treated with primary radical radiotherapy for prostate cancer in Sweden 1998-2016. We calculated hazard ratios (HRs) with 95% confidence intervals (CIs) of the association between the following exposure groups and outcome: conventionally fractionated external beam radiotherapy (EBRT) to 78 Gy (39 x 2 Gy), EBRT combined with high dose-rate brachytherapy (HDR-BT) (25 x 2 Gy + 2 x 10 Gy), conventionally fractionated EBRT to 70 Gy (35 x 2 Gy), and moderately hypofractionated (M-HF) dose-escalated EBRT (29 x 2.5 Gy or 22 x 3 Gy). Results : 7,296 men received conventionally fractionated EBRT to 78 Gy, 4,657 EBRT combined with HDR-BT, 1,672 conventionally fractionated EBRT to 70 Gy, and 1,539 M-HF EBRT. Using EBRT to 78 Gy as the reference, the multivariable HRs (95% CIs) of prostate cancer death was 0.64 (0.53-0.78) for EBRT combined with HDR-BT, 1.00 (0.80-1.27) for EBRT to 70 Gy, and 1.51 (0.99-2.32) for M-HF EBRT. The multivariable HRs (95% CIs) for death from any cause were 0.79 (0.71-0.88), 0.99 (0.87-1.14), and 1.12 (0.88-1.42), respectively. The lower risk of prostate cancer death comparing EBRT combined with HDR-BT to conventionally fractionated EBRT to 78 Gy was more pronounced for men with high-risk or poorly differentiated tumors. Conclusions : In this study, EBRT combined with HDR-BT was the most effective radiotherapy treatment regimen, especially for poorly differentiated tumors. Randomized trials comparing EBRT combined with HDR-BT to dose-escalated EBRT should be a priority.
JNCI Cancer Spectrum 2020