Conformal Proton Beam Therapy of Prostate cancer Report of Long-term PSA Based Outcomes in Over Twelve Hundred Patients
James Metz, MD
OncoLink Associate Editor
Last Modified: October 25, 2000
Presenter: C. J. Rossi
Affiliation: Loma Linda University
Conformal proton beam therapy for prostate cancer has been performed for almost a decade at Loma Linda University Medical Center. This presentation is an update of the outcomes based on PSA.
Materials and Methods:
- 1257 patients with localized prostate cancer were treated with protons between 10/91-12/97.
- The patients had T1c-T3 tumors, PSA < 50 ng/ml
- Patients were treated with conformal protons to a dose of 74-75 Cobalt-Gray Equivalents (CGE) in fractions of 1.8-2 CGE.
- PSA was obtained 4 months after completion of therapy and then every 6 months.
- The median follow-up was 3 1/2 years.
- The 7 year actuarial biochemical disease free survival for the entire group was 79%.
- Failure based on pretreatment PSA was 95% (< 4 ng/ml), 86% (4-10 ng/ml), 67% (10-20 ng/ml), and 56% (20-50 ng/ml).
- Failure based on PSA nadir was 91% (< 0.51 ng/ml), 77% (0.51-1 ng/ml), and 35% (if the PSA never fell below 1 ng/ml)
- The rate of RTOG Grade 3 and 4 toxicity was only 0.3%.
- The results of conformal proton beam therapy are comparable to the best radical prostatectomy results.
- There is minimal toxicity associated with treatment of prostate cancer with protons.
- Proton therapy is an effective option for the treatment of prostate cancer.
- Both the biochemical DFS and toxicity profiles compare favorably to conventional photons and radical prostatectomy.
- The optimal dose for treatment with protons is still not known, but a recently completed Phase III trial of dose escalation with proton therapy may help to answer this question.