What Dose of External-Beam Radiation is High Enough for Prostate Cancer?

The study cohort consisted of 1,530 men treated with three-dimensional conformal external-beam radiotherapy between 1989 and 2002. Patients were divided into four isocenter dose groups: <70 Gy (n = 43), 70–74.9 Gy (n = 552), 75–79.9 Gy (n = 568), and ≥80 Gy (n = 367). Radiotherapy dose was significant in multivariate analyses for FFBF (ASTRO and Phoenix) and FFDM. Adjusted 5-year estimates of ASTRO FFBF for the four dose groups were 60%, 68%, 76%, and 84%. Adjusted 5-year Phoenix FFBFs for the four dose groups were 70%, 81%, 83%, and 89%. Adjusted 5-year and 10-year estimates of FFDM for the four dose groups were 96% and 93%, 97% and 93%, 99% and 95%, and 98% and 96%. Dose–response functions showed an increasing benefit for doses ≥80 Gy.

Conclusions: Doses of ≥80 Gy are recommended for most men with prostate cancer.