Reirradiation of Prostate Cancer Local Failures After Previous Curative Radiation Therapy: Long-Term Outcome and Tolerance

Purpose: To evaluate the safety, feasibility, side-effect profile, and proof of concept of external beam radiation therapy (EBRT) with or without a brachytherapy (BT) boost for salvage of exclusive local failure after primary EBRT for prostate cancer. Methods and Materials: Fourteen patients with presumed exclusive local recurrence after primary EBRT with or without BT were considered eligible for reirradiation. The median normalized total dose in 2-Gy fractions (NTD2Gy, alpha/beta ratio Z = 1.5 Gy) was 74 Gy (range, 66-98.4 Gy) at first irradiation. Median time between the first irradiation and the reirradiation was 6.1 years (range, 4.7-10.2 years). Results: Between 2003 and 2008 salvage treatment was delivered with a median NTD2Gy of 85.1 Gy (range, 70-93.4) to the prostate with EBRT with (n=10) or without (n=4) BT. Androgen deprivation was given to 12 patients (median time of 12 months). No grade >= 3 toxicity was observed during and within 6 weeks after RT. After a median follow-up of 94 months (range, 48-172 months) after salvage RT, 5-year grade >= 3 genitourinary and gastrointestinal toxicity-free survival figures were 77.9% +/- 11.3% and 57.1% +/- 13.2%, respectively. Four patients presented with combined grade 4 genitourinary/gastrointestinal toxicity. The 5-year biochemical relapse-free, local relapse-free, distant metastasis-free, and cancer-specific survival rates were 35.7% +/- 12.8%, 50.0% +/- 13.4%, 85.7% +/- 9.4%, and 100%, respectively. Conclusion: Salvage whole-gland reirradiation for patients with a suspicion of exclusive local recurrence after initial RT may be associated with a high rate of severe radiation-induced side effects and poor long-term biochemical and local control. (C) 2016 Elsevier Inc. All rights reserved.