Treating intermediate-risk prostate cancer with hypofractionated external beam radiotherapy alone.

Abstract

Intermediate-risk prostate cancer has been treated in many ways; the most effective treatment is uncertain. Hypofractionated external beam radiotherapy (HyRT) is a short and convenient alternative treatment. We report our results of HyRT in intermediate-risk patients. Eighty two patients with intermediate-risk prostate cancer were treated with 3-dimensional conformal HyRT plans to the dose of 66 Gy/22 fractions prescribed at the isocenter without hormones. Intermediate-risk was defined as clinical stage T2b-T2c, or pre-treatment PSA between 10 and 20 ng/mL, or Gleason Score equal 7. The planning target volume consisted of the prostate plus a uniform 7 mm margin. Toxicity was prospectively graded by the Common Terminology Criteria version3. Biochemical relapse was defined as post-radiotherapy nadir PSA+2 ng/mL. With a median follow-up of 51 months, 5-year actuarial biochemical recurrence free survival is 95.4%. At the last follow-up visit, grade ≥ 2 late gastro-intestinal and genito-urinary toxicity rates were 2% and 7%, respectively. No patient ever developed grade 4 or 5 toxicity. HyRT to a dose of 66 Gy in 22 fractions as a single treatment modality is convenient for patients and for the health care system and appears to provide similar results to other treatment choices.