title: Clinicohistological characteristics of renal cell carcinoma in children: A multicentre study.
abstract: BACKGROUND
  In this retrospective multicentre study, we compared the clinicohistological characteristics of renal cell carcinoma (RCC) between pediatric and adult patients.
  
  
  METHODS
  Data for patients who underwent radical or partial nephrectomy for RCC between 1988 and 2014 at multiple institutions were collected. Patients were divided into 2 groups according to age at diagnosis: pediatric patients (age ≤18 years) and adult patients (age ≥40 years). The groups were compared for clinical and pathologic variables, and survival analysis was performed.
  
  
  RESULTS
  The median follow-up period was 64 (range: 30-91) months for pediatric patients versus 44 (range: 19-59) months for adult patients (p = 0.026). Pediatric patients were mostly female (p = 0.003), had symptoms at presentation (p < 0.001), and had a high-stage tumour (p = 0.014) than adult patients. Among the symptomatic patients, gross hematuria was the most common symptom. The median tumour size was not different between groups. Regarding histologic types, pediatric patients had more papillary tumours (p < 0.001), more unclassified tumours (p < 0.001), and fewer clear cell carcinomas (p < 0.001). Five-year cancer-specific survival rates were 85% and 87.4% in pediatric and adult patients, respectively (log rank p = 0.901). Recurrence-free survival was better in adult patients, although this did not reach statistical significance (log rank p = 0.272). This study has several limitations, including its retrospective nature and the relatively small number of pediatric RCC cases.
  
  
  CONCLUSIONS
  RCC in children is rare and is characterized by features that differ from those in adult RCC. Prognosis did not differ between groups.
authors.affiliation: Department of Urology, Dongnam Institute of Radiological & Medical Sciences Cancer center, Busan, Korea;
authors.forename: Jeong Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea;
authors.forename: Seong Il
authors.initials: SI
authors.lastname: Seo
authors.affiliation: Department of Urology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea;
authors.forename: Cheryn
authors.initials: C
authors.lastname: Song
authors.affiliation: Department of Urology, Center for Prostate Cancer, National Cancer Center, Goyang, Korea;
authors.forename: Jinsoo
authors.initials: J
authors.lastname: Chung
authors.affiliation: Department of Urology, Seoul National University Hospital, Seoul, Korea;
authors.forename: Cheol
authors.initials: C
authors.lastname: Kwak
authors.affiliation: Department of Urology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Sung-Hoo
authors.initials: SH
authors.lastname: Hong