Short-term high precision radiotherapy for early prostate cancer with concomitant boost to the dominant lesion: ad interim analysis and preliminary results of Phase II trial AIRC-IG-13218

Objective:To report preliminary results of a cutting edge extreme hypofractionated treatment with concomitant boost to the dominant lesion for patients with early stage prostate cancer (PCa).Methods:AIRC-IG-13218 is a prospective Phase II trial started in June 2015. Patients with low and intermediate risk PCa who met the inclusion criteria underwent extreme hypofractionated radiotherapy to the prostate (36.25 Gy in 5 fractions) and a simultaneous integrated boost to the dominant intraprostatic lesion (DIL) to 37.5 Gy. The DIL was identified by a multiparamentric MRI (mpMRI) co-registered with planning CT. Toxicity was assessed according to CTCAE v4.0 and RTOG/EORTC criteria. The preliminary evaluation of the first 13 patients was required to confirm the feasibility of the treatment before completing the enrollment of 65 patients.Results:The first 13 patients completed the treatment between June 2015 and February 2016. With a median clinical follow-up of 17 months (range 11–26), no Grade 3 or 4 early toxic...