Moderate hypofractionated radiotherapy (HypoRT) is an attractive alternative to conventionally fractionated radiotherapy for prostate cancer. However, most studies using HypoRT only included the prostate as the target volume. We report long-term outcomes of patients with high-risk prostate cancer treated with androgen deprivation therapy (ADT) and HypoRT to the prostate and nodal areas with a simultaneous integrated boost technique.
Patients with localized, high-risk prostate cancer entered a prospective Phase I/II study with a HypoRT regimen of 60 Gy/ 20 fractions (4 weeks) to the prostate volume while the nodal areas received 44 Gy in the same 20 fractions delivered with IMRT with a simultaneous integrated boost technique. ADT started 2-3 months before HypoRT. Toxicity was prospectively assessed according to the Common Terminology Criteria for Adverse Events.v3. Outcomes rates were calculated by the actuarial method of Kaplan-Meier from the date of last radiation treatment until date of event.
We report on the first 105 patients treated between October/2010 and February/2014. Median follow up was 74 months with 97% of patients followed for more than 36 months. Median ADT duration was 18 months. The worst grade 2 or higher late gastrointestinal (GI) or genitourinary (GU) toxicity was seen in 7% and 9%, respectively. There was no grade 4 or 5 toxicity. At the last follow-up, the rates of grade >2 GI or GU toxicity were 2% and 3%, respectively, with no residual grade>3 toxicity. The 5- and 7-year actuarial overall survival and relapse free survival are 91% and 85% and 87% and 81%, respectively.
The longest follow-up report of moderate HypoRT (plus ADT) to the prostate and pelvic nodes shows that this approach is feasible, well tolerated and effective. It is convenient to patients and health system. A larger randomized trial using this approach is warranted.
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