Acute and late toxicity in high-risk prostate cancer patients treated with androgen suppression and hypofractionated pelvic radiation therapy.

PURPOSE: To report acute and late toxicity rates in patients with high-risk prostate cancer treated with androgen deprivation therapy (ADT) and moderate hypofractionated radiation therapy (HypoRT) to the prostate and nodal areas.

METHODS AND MATERIALS: Patients with localized, high-risk prostate cancer were treated with a HypoRT regimen of 60 Gy in 20 fractions (4 weeks) to the prostate volume while the nodal areas received 44 Gy in the same 20 fractions delivered with intensity modulated RT with a simultaneous integrated boost technique. ADT started 2 to 3 months before HypoRT and was given to all patients. Acute and late toxicity were prospectively assessed and graded according to the Common Terminology Criteria for Adverse Events, version 3.

RESULTS: A total of 105 patients treated between September 2010 and November 2013 were reviewed. Median follow-up was 41 months, with 97% of patients followed for more than 26 months. Median ADT duration was 18 months. Acute grade 2 or higher gastrointestinal (GI) or genitourinary (GU) toxicity was seen in 18 (17%) and 19 (17%) patients, respectively, with only 1 and 3 patients experiencing either a GI or GU acute grade 3 toxicity. The worst grade 2 or higher late GI and GU toxicity were seen in 7 (7%) and 8 (8%) patients, respectively. There was no grade 4 or 5 toxicity. At the last follow-up, the rate of grade 2 GI and GU toxicity was 5% and 3%, respectively, with no residual grade ≥3 toxicity. The 48-month actuarial progression free survival is 82%.

CONCLUSIONS: ADT with moderate HypoRT delivered with IMRT and an integrated simultaneous boost to the prostate (60 Gy) and pelvic nodes (44 Gy) in 20 fractions is feasible and well tolerated. This approach shortens treatment duration and is convenient for patients and the health system, and its results support a randomized trial.