Stage I epithelial or stromal type Wilms tumors are low risk tumors: An analysis of patients treated on the SIOP-WT-2001 protocol in the UK-CCLG and GPOH studies (2001-2020)

BackgroundPatients treated with preoperative chemotherapy with stage I intermediate-risk Wilms tumor (IR-WT) represent the largest group of patients with Wilms tumor (WT), and they have excellent outcomes. MethodsThe authors performed a retrospective analysis of patients with stage I epithelial (ET-WT) or stromal type WT (ST-WT) treated pre- and postoperatively according to the International Society of Paediatric Oncology-WT-2001 protocol in the UK Children's Cancer and Leukaemia Group and Gesellschaft fur Padiatrische Onkologie und Hamatologie groups' participation in the relevant WT trials and studies (2001-2020). ResultsThere were 880 patients with stage I IR-WT, including 124 with ET-WT, 156 with ST-WT, and 600 with other IR-WT (oIR-WT). Patients with stage I ET-WT or ST-WT were significantly younger than patients with oIR-WT, represented a large proportion of stage I WTs in their groups, and tumors showed poor histologic response to preoperative chemotherapy. The 5-year event-free survival (EFS) estimates for patients with stage I ET-WT (96.8% +/- 1.8 SE) or ST-WT (96.8% +/- 1.6 SE) were significantly better than for patients with oIR-WT (90.3% +/- 1.3 SE) (p = .014 and p = .009, respectively). A multivariate analysis showed that histologic type (ET-WT or ST-WT) remained a significant factor for EFS when adjusted for age and gender (p = .032 and p = .022, respectively). In both groups, relapses occurred in 3.2% of patients, and the overall survival was 99.2%. ConclusionsThe results suggest that stage I ET-WT or ST-WT could be regarded as low-risk WT, for which omission of postoperative chemotherapy should be considered. Plain Language Summary Patients with pretreated intermediate-risk Wilms tumor (WT) represent the largest group of patients with WT.This study reports the outcomes of patients with stage I epithelial type (ET-WT) or stromal type WT (ST-WT).These patients were significantly younger and had a larger proportion of stage I cases than patients with other intermediate-risk WT (oIR-WT).The event-free survival for patients with stage I ET-WT and ST-WT was significantly better than for patients with oIR-WT.Rare relapses were curable resulting in 99.2% overall survival.

Automated summary

This study analyzed the outcomes of patients with stage I epithelial type (ET-WT) or stromal type WT (ST-WT) treated with preoperative chemotherapy. The results showed that patients with stage I ET-WT or ST-WT had significantly better event-free survival compared to patients with other intermediate-risk WT. The study suggests that omission of postoperative chemotherapy could be considered for low-risk ET-WT or ST-WT patients.