• Nadia Di Muzio, Claudio Fiorino, Cesare Cozzarini, Filippo Alongi, Sara Broggi, Paola Mangili, Giorgio Guazzoni, Riccardo Valdagni, Riccardo Calandrino, and Ferruccio Fazio.
• Department of Radiotherapy, Scientific Institute San Raffaele, Milan, Italy. dimuzio.nadia@hsr.it
• Int. J. Radiat. Oncol. Biol. Phys. 2009 Jun 1; 74 (2): 392-8.

PurposeTo report planning and acute toxicity data of the first 60 patients treated within a Phase I-II study with moderate hypofractionation by image-guided helical tomotherapy.Methods And MaterialsVarious clinical target volumes (CTVs) were defined: CTV1-pelvic nodes; CTV2-upper portion of seminal vesicles; CTV3-lower portion of SV; CTV4-prostate; overlap between planning target volume (PTV) 4 and rectum. Different doses to each PTV were simultaneously delivered in 28 fractions. For 31 low-risk patients: 56.0, 61.6, and 71.4 Gy for PTV2-4, respectively; for 20 intermediate-risk patients: 51.8, 61.6, 65.5, and 74.2 Gy for PTV1-4, respectively; for 9 high-risk patients: 51.8 and 65.5 Gy for PTV1-2 and 74.2 Gy for PTV3-4. For all patients, the dose to overlap was 65.5 Gy.ResultsThe mean fraction of rectum receiving more than 65 Gy (V65) and rectal Dmax were 10% and 70.8 Gy respectively. In cases of pelvic node irradiation, the intestinal cavity (outside PTV) receiving > 45 and 50 Gy was 86 and 12 cc, respectively. A homogeneous dose distribution within each PTV was guaranteed. Acute genitourinary toxicity according to RTOG scoring system was as follows: 21/60 (35%) Grade 1, 12/60 (20%) Grade 2, 2/60 (3%) Grade 3. Acute rectal toxicities were: 18/60 (30%) Grade 1. Twelve (20%) patients showed Grade 1 upper intestinal toxicity (uGI). No patients experienced > or = Grade 2 acute rectal or uGI side effects.ConclusionsThis study shows excellent results with regard to acute toxicity. Further research is necessary to assess definitive late toxicity and tumor control outcome.

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