Tumor volume reduction after neoadjuvant chemotherapy in childhood nephroblastoma: radiological, histopathological, and clinical correlates in Tanzania.

Nephroblastoma is the most common pediatric kidney cancer, accounting for approximately 6% of childhood malignancies. Neoadjuvant chemotherapy plays an important role in reducing tumor size and facilitating safer surgery. This study aimed to determine radiological tumor volume reduction in nephroblastoma after neoadjuvant chemotherapy and its associations with histopathological subtypes and clinical outcomes among children in XXXX country. A retrospective cohort study was conducted among 126 children aged 6 months to <18 years with histopathologically confirmed nephroblastoma treated under the International Society of Pediatric Oncology (SIOP) umbrella protocol at two tertiary oncology centers in XXXX between 2021 and 2023. Tumor volumes were measured from pre- and post-neoadjuvant chemotherapy abdominal pelvic computed tomography scans to calculate volume reduction ratios. SPSS v26 was used for analysis, with logistic regression and chi-square tests used to assess associations with histopathology and clinical outcomes. The median age at diagnosis was 36 months, with female predominance (57.9%), and most lacked health insurance (71.4%). Blastemal histological subtype was the most common subtype (40.5%). Post neoadjuvant chemotherapy, 62.7% achieved a good response, while 40.5% had residual tumor volumes >500 ml. Stromal histology was strongly associated with large residual (AOR=15.00; 95% CI: 4.00–56.13; p < 0.001). Tumor volume reduction also varied by treatment center and insurance status Histopathological subtypes are key determinants of the radiological response following neoadjuvant chemotherapy. Differences by treatment center and insurance status suggest that healthcare-related factors may also influence outcomes, although the treatment center effect showed borderline statistical significance. Further large-scale studies are needed to clarify these associations in resource-limited settings. • CT-based tumor volume reduction predicts chemo response in nephroblastoma • Histopathology strongly influences radiological tumor shrinkage • Stromal subtype linked to large residual tumor volumes post-therapy • Dominant blastemal subtype associated with favourable volume reduction • Insurance status and center affect treatment response outcomes