Wilms tumor, the most common pediatric kidney cancer, presents ongoing challenges for optimal treatment strategies. While the Children’s Oncology Group (COG) generally advises immediate surgical resection, this is typically bypassed for patients with specific cancer syndromes or bilateral disease. In contrast, the Société Internationale d’Oncologie Pédiatrique (SIOP) advocates for neoadjuvant chemotherapy (NAC) prior to surgery. However, NAC’s extended duration and potential toxicity raise concerns about determining the best treatment length, often debated between six and twelve weeks. Our study analyzed how NAC duration affects tumor reduction in Wilms tumor patients.
Through a retrospective review of institutional cases from 2006 to 2022, we examined 28 patients with Wilms tumor who received NAC due to syndromic or bilateral disease. We gathered data on demographics, presentation, chemotherapy type, and cancer syndromes, and collected radiologic imaging data at diagnosis, six weeks, and twelve weeks. Tumor volume was calculated using the prolate ellipsoid formula, and Kruskal-Wallis and Wilcoxon rank-sum tests were employed for statistical analysis.
Among the patients, 19 (67.9%) completed a 12-week NAC course, while nine (32.1%) proceeded to surgery after six weeks. Stage V disease was initially found in 57.1% of cases. Tumor volumes decreased significantly: median volume was 129.9 cm³ at diagnosis, 26.1 cm³ at six weeks, and 7.7 cm³ at twelve weeks (p<0.001). Notably, 88.9% showed a 20% or more volume reduction from baseline to six weeks, and all patients displayed reductions from baseline to twelve weeks. The median tumor shrinkage rate was 80% from baseline to six weeks and 90% from six to twelve weeks (p=0.041), indicating sustained benefit. These findings suggest that extended NAC may be advantageous, warranting future guideline adjustments that account for patient comorbidities and disease characteristics.
