Proton therapy for prostate cancer: the initial Loma Linda University experience.

Abstract

We analyzed results of conformal proton radiation therapy for localized prostate cancer, with emphasis on biochemical freedom from relapse. Analyses were performed for 1255 patients treated between October 1991 and December 1997. Outcomes were measured on primarily in terms of biochemical relapse and toxicity. The overall biochemical disease-free survival rate was 73%, and was 90% in patients with initial PSA <or=4.0; it was 87% in patients with posttreatment PSA nadirs <or=0.50. Rates dropped with rises in initial and nadir PSA values. Long-term survival outcomes were comparable with those reported for other modalities intended for cure. Conformal proton radiation therapy at the reported dose levels yielded disease-free survival rates comparable with other forms of local therapy, and with minimal morbidity. Dose-escalation strategies are being implemented to further improve long-term results.