2020 Volume 57 Issue 3 Pages 318-325
Introduction: Past clinical studies by the Japan Wilms Tumor Study Group (JWiTSG) revealed that treatments for bilateral Wilms’ tumors (BLWT) started with primary surgery (nephron-sparing tumor resection or nephrectomy). However, results of the JWiTS-1 studies revealed the problem of preserving renal function. Therefore, a new protocol study for BLWT (RTBL) was started in 2014. Here, we report the results of the RTBL14 clinical study.
Methods: In this study, initial chemotherapy using actinomycin-D, vincristine and doxorubicin was started without tumor biopsy. Reduction in tumor size was evaluated by a central radiological review, and nephron-sparing surgery was performed to preserve as much of the renal parenchyma as possible. The primary endpoint of the RTBL study was the success rate of bilateral renal preservation one year after treatments.
Results: Only 23 institutions joined the study, and only three patients were enrolled within four years. It was difficult to collect enough cases within the study period, so the study was abandoned in March 2019. Among the three patients, two completed the study protocol; however, the protocol was stopped because of intratumoral hemorrhage in one patient. The bilateral renal parenchyma was successfully preserved in only one patient.
A questionnaire survey was conducted to identify the reasons why institutions did not join the RTBL14 study. The most common reasons were the rarity of BLWT and the difficulty of the ethical review.
Conclusions: It is difficult to perform a clinical study of rare conditions such as BLWT. International collaboration is necessary to perform clinical studies of extremely rare tumors.
