[1] Univ Florence, Radiat Oncol Unit, Azienda Osped Univ Careggi, Florence, Italy
[2] Univ Florence, Dept Biomed Expt & Clin Sci Mario Serio, Florence, Italy
[3] Inst Canc Res Prevent & Clin Network, Canc Risk Factors & Life Style Epidemiol Unit, Florence, Italy
[4] Univ Hosp Modena, Dept Oncol & Hematol, Radiotherapy Unit, Modena, Italy
[5] Univ Perugia, Radiat Oncol Sect, Dept Med & Surg, Perugia, Italy
[6] Univ Roma Tor Vergata, Radiat Oncol, Dept Biomed & Prevent, Rome, Italy
[7] Fdn Policlin Univ A Gemelli IRCCS, UOC Radioterapia Oncol, Dipartimento Diagnost Immagini Radioterapia Oncol, Rome, Italy
[8] Azienda USL IRCCS Reggio Emilia, Unit Radiotherapy, Reggio Emilia, Italy
[9] Univ Brescia, Dept Radiat Oncol, Brescia, Italy
[10] Univ Messina, Radiat Oncol Unit, Dept Biomed Dent Sci & Morphol & Funct Images, Messina, Italy
[11] SM Grazie Hosp, Med Oncol Unit, Naples, Italy
[12] Univ Calif Davis, Ctr Comprehens Canc, Sacramento, CA USA