Postchemotherapy tumor volume as a prognostic indicator in Wilms tumor: A single-center experience from South India

Background: Optimal risk stratification is the key to minimizing relapse and toxicity in children with Wilms tumor (WT). The study evaluated poor tumor volume response to chemotherapy as a risk factor that predicts relapse.

Procedure: Children with WT who were treated between 2005 and 2020 at the center were analyzed. Tumor volumes at the time of diagnosis and after preoperative chemotherapy were calculated from cross-sectional imaging. The International Society of Paediatric Oncology (SIOP)-WT-2001 protocol was used for treatment. The area under a receiver operating characteristic curve was estimated to ascertain the ability of tumor volume to predict relapse.

Results: Ninety-five patients with a median age of 40 months were included. A postchemotherapy tumor volume cutoff of 270 ml was ascertained to have the best predictive value for relapse. Patients with a tumor volume of <270 ml following preoperative chemotherapy had a better 3-year event-free survival (EFS) than those with a tumor volume of ≥270 ml (89.8% ± 4.0% vs. 57.4% ± 12.5%, p = .001). The data demonstrated that a tumor volume of ≥270 ml after chemotherapy was associated with an increased risk of relapse (hazard ratio [HR]: 5.3, p = .006). The EFS in patients with an epithelial or stromal type of histopathology was not affected by the tumor volume response (p = .437). Conversely, patients with other types of intermediate-risk histopathology who had a poor tumor volume response had an inferior survival (3-year EFS 51.4% ± 18.7%, p = .001).

Conclusion: A postchemotherapy tumor volume cutoff of ≥270 ml emerged as a strong predictor of relapse in a low- and middle-income country (LMIC) center study of WT treated with the SIOP protocol.