1. Johns Hopkins University School of Medicine, Baltimore, MD, USA; Naples Anesthesia and Pain Associates, Naples, FL, USA
2. La Maddalena Cancer Centre, Palermo, Italy
3. University Hospital Virgen Macarena, Sevilla, Spain
4. AZ Nikolaas, Sint-Niklaas, Belgium
5. Portuguese Institute of Oncology, Porto, Portugal
6. University Hospital, Wroclaw, Poland
7. AZ Nikolaas Campus Moerland, Sint-Niklaas, Belgium
8. POKO Poprad, Poprad, Slovak Republic
9. Palliative Hospice, University Hospital, Wroclaw, Poland
10. Masaryk Memorial Cancer Institute, Brno, Czech Republic