Outcome of renal tumors registered in Japan Wilms Tumor Study-2 (JWiTS-2): A report from the Japan Children's Cancer Group (JCCG)

Japan Wilms Tumor Study-2 (JWiTS-2) mandated central pathology review for all case registrations. The study aimed to compare the outcomes of patients with unilateral Wilms tumor enrolled on the JWiTS-1 and JWiTS-2 trials.

The JWiTS-2 trial (2006-2014), a prospective, single-arm study, required compulsory submission of histologic slides to central pathology, while in the JWiTS-1 trial, such submission was not compulsory. Relapse-free survival (RFS) and overall survival (OS) versus cases in the JWiTS-1 trial (1996-2005) were statistically evaluated.

Of 277 enrolled patients with primary renal tumors diagnosed by the central pathology review system, 225 patients with unilateral renal tumors were followed up over 9 years. The RFS and OS of Wilms tumor (n = 178) were 90.4% (P = 0.0003) and 96.8% (P = 0.054), respectively, as compared to 74.9% and 89.4% in JWiTS-1. RFS rates of stages I-III Wilms tumor in JWiTS-2 were more than 90%, although the outcome of stage IV Wilms tumor was significantly poorer (RFS: 66.2%) (P = 0.0094). RFS and OS of clear cell sarcoma of the kidney (CCSK; n = 31) were 82.4% (P = 0.30) and 91.3% (P = 0.42), respectively, as compared to 68.8% and 81.3% in JWiTS-1, and those of rhabdoid tumor of the kidney (RTK; n = 16) were 18.8% (P = 0.88) and 25.0% (P = 0.80), respectively, as compared to 23.5% and 23.5% in JWiTS-1.

RFS and OS for stages I-III Wilms tumor were improved in JWiTS-2 compared to JWiTS-1, whereas outcomes for stage IV Wilms tumor, CCSK, and RTK did not improve.

Pediatric blood & cancer. 2018 Apr 06 [Epub ahead of print]

Tsugumichi Koshinaga, Tetsuya Takimoto, Takaharu Oue, Hajime Okita, Yukichi Tanaka, Miwako Nozaki, Kunihiko Tsuchiya, Eisuke Inoue, Masayuki Haruta, Yasuhiko Kaneko, Masahiro Fukuzawa

Department of Pediatric Surgery, Nihon University School of Medicine, Tokyo, Japan., Division of Registration and Research for Childhood Cancer, National Center for Child Health and Development, Tokyo, Japan., Department of Pediatric Surgery, Hyogo College of Medicine, Nishinomiya, Japan., Department of Pathology, Keio University School of Medicine, Tokyo, Japan., Department of Pathology and Clinical Research Institute, Kanagawa Children's Medical Center, Yokohama, Japan., Department of Radiology, Dokkyo Medical University Saitama Medical Center, Koshigaya, Japan., Department of Pediatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan., Division of Medical Informatics, St. Marianna University School of Medicine, Kawasaki, Japan., Research Institute for Clinical Oncology, Saitama Cancer Center, Kitaadachi-gun, Japan., Osaka Women's and Children's Hospital, Izumi, Japan.