Hypofractionated adjuvant radiotherapy with helical Tomotherapy after radical prostatectomy: Planning data and toxicity results of a Phase I–II study

PurposeTo report on planning and toxicity findings of hypofractionated adjuvant radiotherapy with helical Tomotherapy (HTT) after radical prostatectomy (RP) for prostate carcinoma (pCa).Methods and materialsFifty consecutive patients submitted to RP for pT2R1/pT3a/pT3b-pN0 pCa were enrolled in a Phase I–II trial to receive 58 Gy/20 fractions (5/week) on tumoral bed.Endpoint was to verify a risk of toxicity and biochemical failure not exceeding that observed in our Institutional 3DCRT, conventionally fractionated series (153 patients).Toxicities were graded according the RTOG scoring system.ResultsExcellent coverage of PTV and high homogeneity of dose distribution were always achieved.Median follow-up was 25 months. Acute G2-3 RTOG genitourinary (GU) and acute G2 intestinal toxicities were similar (12% vs 15.6% and 4% vs 7%, respectively), while acute G2 proctitis was 0% vs 9% in HTT and 3DCRT group, respectively. Similarly, late Grade ⩾2 gastrointestinal sequelae were 0% vs 8.5%. The incidence of late urethral stricture, 8% and 9% in HTT and 3DCRT group, respectively, is comparable to that of RP-only series.ConclusionsAcute toxicity and early late toxicity outcomes of a moderately hypofractionated regimen with HTT post-RP are excellent. A longer follow-up is needed to fully assess the validity of this approach.