1. Department of Oncology and Surgical Oncology for Children and Youth, Institute of Mother and Child, 01-211 Warsaw, Poland
2. 1st Department of Oncologic Surgery, Maria Sklodowska Curie Memorial National Cancer Center, 44-100 Gliwice, Poland
3. Department of Clinical Pediatrics, Head and Neck Surgery Clinic for Children and Young Adults, University of Warmia and Mazury, 10-709 Olsztyn, Poland
4. Pediatric Surgery and Urological Department, Upper Silesian Child Health Center in Katowice, Silesian University of Medicine, 40-052 Katowice, Poland