The efficacy and safety of conventional and hypofractionated high-dose radiotherapy for prostate cancer in an elderly population: a subgroup analysis of the CHHiP trial
Mené sur 3 216 patients atteints d'un cancer de la prostate et ayant reçu un traitement anti-androgénique d'une durée de 3 à 6 mois, cet essai évalue, en fonction de deux catégories d'âge (inférieur à 75 ans et 75 ans ou plus), l'efficacité, du point de vue du taux d'échec biochimique et clinique, et la toxicité d'une radiothérapie hypofractionnée par rapport à une radiothérapie conventionnelle
Introduction : Outcome data on radiotherapy for prostate cancer in an elderly population are sparse. The CHHiP trial provides a large, prospectively collected, contemporary dataset in which to explore outcomes by age. Methods and Materials : CHHiP participants received 3-6 months of androgen deprivation therapy and were randomly assigned (1:1:1) to receive 74Gy in 37 fractions (conventional fractionation), 60Gy in 20 fractions or 57Gy in 19 fractions. Toxicity was assessed using clinician-reported and patient-reported outcome (CRO/PRO) questionnaires. Participants were categorised as aged less than 75 (<75) or 75 years and older (75+).Outcomes were compared by age-group. Results : 491/3216 (15%) were 75+. There was no difference in biochemical or clinical failure (BCF) rates between the <75 and the 75+ group for any of the fractionation schedules. In the 75+ group BCF-free rates favoured hypofractionation and at 5 years were 74Gy: 84.7%, 60Gy: 91%, 57Gy: 87.7%. The incidence of CRO (G3) acute bowel toxicity was 2% in both age-groups. Grade 3 acute bladder toxicity was 8% and 7%. Five year cumulative incidence of CRO grade 2+ late bowel side effects was similar in both age groups. However, in the 75+ group, there was a suggestion of a higher cumulative incidence of bowel bother (≥small) with 60Gy compared to 74Gy and 57Gy. Patient-reported bladder bother was slightly higher in the 75+ group than the <75 group and there was a suggestion of a lower cumulative incidence of bladder bother with 57Gy compared to 74Gy and 60Gy in the 75+ group which was not evident in those <75. Conclusion : Hypofractionated radiotherapy appears to be well tolerated and effective in men over 75. The 57 Gy schedule has potential advantages in that it may moderate long term side effects without compromising treatment efficacy in this group.