[Long-term follow-up report of multicenter clinical study on childhood renal tumor]

Objective: To find the possibility of establishing multicenter cooperative group in China and to analyze the data and provide evidences for further revision of the protocol for improving the studies on renal tumor. Method: The multicenter renal tumor cooperative group was established under the Chinese Children Cancer Group. The diagnosis and staging criteria, the regulation for surgery, chemotherapy and radiation therapy were included in the protocol for renal tumor studies. Uniform data collection form was sent out to all the centers and collected data back by e-mail. All the cases have to meet the data collection criteria including pathological diagnosis, staging and follow-up. Result: This protocol was administered in 21 pediatric centers, 11 of them sent back on date as requested. Totally 361 cases were recruited and another 19 cases were excluded of the analysis because they did not fit or not registered fully as requested. The age was between 1 to 163 months, median 28 months. A percent of 65.9%(238/361)the patients was diagnosed at the age of younger than 3 years. Male and female ratio was 1.4∶1. After followingup for 24-204 months (medium 57 months), 5 year event-free survival (EFS) was 80.0% for all group, 81.2% (300 cases) for FH, 71.7% (32 cases) for UFH, 68.8% (17 cases) for clear cell, and 60.0% (5 cases) for rhabdoid tumor( χ²=7.795, P=0.099). In FH group, 5 year EFS was 91.7% for stage Ⅰ (93 cases), 78.0% (87 cases) for stage Ⅱ, 78.3% (81 cases) for stage Ⅲ, 77.2% and 50.4% for stage Ⅳ (31 cases) and V (8 cases) (χ²=11.787, P=0.019 ). Totally 177 cases needed radiation therapy based on protocol guideline, but only 97 of them were radiated because of different reasons. Five year EFS for 97 cases radiated and 80 cases not radiated were 83.1% and 64.5% (χ²=9.419, P=0.002 ). Sixty-four cases (17.7%) died of disease progression, relapse and abandonment of treatment. Conclusion: Multi-center cooperative group model for childhood renal tumor is feasible in China. The result is reasonable, but can be improved further. The result is the same between FH stage Ⅱ and Ⅲ. And it may be related to down-staging Ⅲ to Ⅱ or under-therapy for stage Ⅱ. Radiation therapy is important for stage Ⅲ and Ⅳ patients, and to which more attention should be paid. The reliability of data collection should be improved further.