[1] Maggiore Hosp, Thorac Endoscopy & Pulmonol Unit, I-40133 Bologna, Italy
[2] Maggiore Hosp, Pathol Unit, I-40133 Bologna, Italy
[3] Maggiore Hosp, Thorac Surg Unit, I-40133 Bologna, Italy
[4] IRCCS Policlin San Matteo, Clin Epidemiol & Biometry Serv, Pavia, Italy