ObjectiveTo investigate the effects of lymph node involvement and dissection number on prognosis in patients with Wilms tumor (also known as nephroblastoma). MethodsClinical data of all the children with Wilms tumor who received standardized treatment in our hospital from January 2010 to December 2019 were collected and retrospectively analyzed. The patients were divided into different groups according to lymph node involvement and sampling number. The survival outcome and 5-year event-free survival (EFS) among different groups were analyzed with Kaplan-Meier survival analysis and Log-rank test

respectively. Pearson’s Chi-squared test was used to compare categorical variables among groups. ResultsA total of 173 patients (81 boys and 92 girls) were enrolled in this study

with a median follow-up of 53 (3~108) months. Among them

23 patients (13.30%) had lymph node involvement

and 150 (86.70%) had not

and the ratio of 5-year EFS was 56.19% and 81.27%

respectively (P<0.000 1). Moreover

the ratio for those with unfavorable histology (uFH) was 25.00% and 71.13% (P<0.000 1)

respectively

and that for those with favorable histology (FH) was 73.33% and 84.16%

respectively in the patients with or without lymph node involvement (P=0.091 8). For the patients with dissected lymph node number of 1~3

4~6

7~9 and >10

the rate of positive lymph node was 4.23%

7.32%

38.46% and 43.75%

respectively (P<0.000 1). There was no significant correction between the dissection number and prognosis in the stage Ⅰ and stage Ⅱ patients (P=0.479 0). ConclusionLymph node involvement is a poor prognostic factor in patients with Wilms tumor

especially in those with uFH. The probability of detecting positive lymph node is higher when the number of dissected node larger than 7

but the dissection number has no effect on prognosis.