Outcomes of Wilms tumor treatment in western Kenya.

Background/objectives: Wilms tumor (WT) is a curable type of cancer with 5-year survival rates of over 90% in high-income countries, whereas this is less than 50% in low- and middle-income countries. We assessed treatment outcomes of children with WT treated at a large Kenyan teaching and referral hospital.

Design/methods: We conducted a retrospective record review of children diagnosed with WT between 2013 and 2016. Treatment protocol consisted of 6 weeks of preoperative chemotherapy and surgery, and 4-18 weeks of postoperative chemotherapy depending on disease stage. Probability of event-free survival (pEFS) and overall survival (pOS) was assessed using Kaplan-Meier method with Cox regression analysis. Competing events were analyzed with cumulative incidences and Fine-Gray regression analysis.

Results: Of the 92 diagnosed patients, 69% presented with high-stage disease. Two-year observed EFS and OS were, respectively, 43.5% and 67%. Twenty-seven percent of children died, 19% abandoned treatment, and 11% suffered from progressive or relapsed disease. Patients who were diagnosed in 2015-2016 compared to 2013-2014 showed higher pEFS. They less often had progressive or relapsed disease (p = .015) and borderline significant less often abandonment of treatment (p = .09). Twenty-nine children received radiotherapy, and 2-year pEFS in this group was 86%.

Conclusion: Outcome of children with WT improved over the years despite advanced stage at presentation. Survival probabilities of patients receiving comprehensive therapy including radiation are approaching those of patients in high-income countries. Additional improvement could be achieved by ensuring that patients receive all required treatment and working on earlier diagnosis strategies.