Long-Term Results of Moderate Hypofractionation to Prostate and Pelvic Nodes Plus Androgen Suppression in High-Risk Prostate Cancer.

PURPOSE

Moderate hypofractionated radiation therapy (HypoRT) is an attractive alternative to conventionally fractionated radiation therapy 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.

METHODS AND MATERIALS

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 intensity modulated radiation therapy with a simultaneous integrated boost technique. ADT started 2 to 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.

RESULTS

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 or genitourinary 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 gastrointestinal or genitourinary toxicity were 2% and 3%, respectively, with no residual grade ≥3 toxicity. The 5- and 7-year actuarial overall survival and relapse free survival were 91% and 85% and 87% and 81%, respectively.

CONCLUSIONS

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 for patients and the health system. A larger randomized trial using this approach is warranted.