1 Institute of Oncology, Ljubljana, Slovenia; Medical Faculty, University of Maribor, Maribor, Slovenia. Electronic address: matjaz.zwitter@guest.arnes.si.
2 University Clinic of Respiratory and Allergic Diseases, Golnik, Slovenia.
3 Institute of Oncology, Ljubljana, Slovenia.
4 Department of Thoracic Surgery, University Clinical Center, Ljubljana, Slovenia.
5 National Institute for Public Health, Ljubljana, Slovenia.