IMRT significantly reduces acute toxicity of whole-pelvis irradiation in patients treated with post-operative adjuvant or salvage radiotherapy after radical prostatectomy

PurposeTo investigate the role of IMRT in reducing the risk of acute genito-urinary (GU), upper gastrointestinal (uGI) and lower gastrointestinal (lGI) toxicity following whole-pelvis irradiation (WPRT) after radical prostatectomy.Patients and methods172 consecutive patients with prostate cancer were post-operatively irradiated to the prostatic bed (PB) and pelvic lymph-nodal area with adjuvant (n = 100) or salvage (n = 72) intent. Eighty-one patients underwent three-dimensional conformal (3DCRT) WPRT, while the remaining 91 underwent IMRT (54/91 with helical tomotherapy (HTT); 37/91 with Linac intensity-modulated RT (LinacIMRT)).ResultsPatients treated with IMRT experienced a decreased risk of acute toxicity. The crude incidence of grade ⩾2 toxicity was GU 12.3% vs. 6.6% (p = 0.19); lGI 8.6% vs. 3.2% (p = 0.14); uGI 22.2% vs. 6.6% (p = 0.004), for 3DCRT and IMRT, respectively. With respect to uGI and lGI, the acute toxicity profile of the HTT patients was even better when compared to that of 3DCRT patients (crude incidence:1.8% and 0.0%, respectively). Treatment interruptions due to uGI toxicity were 11/81 in the 3DCRT group vs. 2/91 in the IMRT group (p = 0.006).ConclusionsThe risk of acute toxicity following post-operative WPRT delivered by means of IMRT was reduced compared to that of 3DCRT. The most significant reduction concerned uGI, mainly owing to better bowel sparing with IMRT.