Prognostic Determinants in Children with Wilms’ tumor Treated with Neoadjuvant Chemotherapy: A Single-center Prospective Cohort from Vietnam

Abstract

Introduction: Evidence on prognostic determinants in Vietnamese children with Wilms’ tumor presenting with imaging-defined risk features remains limited despite internationally standardized use of neoadjuvant chemotherapy. To describe treatment outcomes and explore factors associated with event-free survival (EFS) in children with unilateral stage II–IV Wilms’ tumor treated with SIOP-2001–based neoadjuvant chemotherapy followed by delayed nephrectomy at a single tertiary center in Vietnam.

Materials and Methods: We conducted a prospective cohort study of 64 consecutive children managed at Children’s Hospital 2 (Ho Chi Minh City) between April 2013 and June 2016, with follow-up through June 2019. Eligibility required ≥1 imaging-defined risk feature on baseline computed tomography. Patients received SIOP-2001–based neoadjuvant chemotherapy (vincristine and actinomycin D with risk-adapted addition of doxorubicin), followed by delayed nephrectomy and postoperative risk-adapted therapy. Tumor volume was calculated by the ellipsoid formula, and relative volumetric response was recorded. Chemotherapy response was assessed using RECIST 1.1. EFS was estimated by Kaplan–Meier analysis. Given the small number of events (n = 4), Cox regression was prespecified as exploratory, with parsimonious multivariable models and emphasis on effect sizes and confidence intervals.

Results: Median tumor volume decreased from 487.9 cm³ to 206.8 cm³ (p < 0.001). Imaging-defined risk features declined substantially (e.g. perirenal fat invasion 85.9%→43.8%, renal/IVC thrombus 20.3%→6.3%, suspicious hilar nodes 20.3%→4.7%, tumor rupture 9.4%→3.2%). Overall response rate was 89.1% (complete or partial response); 10.9% had stable or progressive disease. At a mean follow-up of 46.9 months, 4 events (2 relapses, 2 deaths) occurred, corresponding to a 4-year EFS of 92.2%. In exploratory multivariable Cox models limited to two predictors, high histopathologic risk and poor chemotherapy response were associated with higher hazards of relapse or death, but with wide confidence intervals reflecting limited precision.

Conclusions: In this exploratory analysis, postoperative histopathologic risk grouping and preoperative chemotherapy response appeared more informative for prognosis than baseline imaging extent. These findings are hypothesis-generating and should be validated in larger multicenter cohorts.