Wilms tumor treatment protocol compliance and the influence on outcomes for children in Tanzania.

Abstract

Standardized Wilms tumor treatment protocols exist for low- and middle-income countries, but outcomes equivalent to high-income countries are not achieved outside of clinical trials. As Wilms tumor treatment protocols in Africa shift with increasing resource capacity, it is not known how treatment compliance to each stage of therapy affects outcomes and where the critical breakpoints are for protocol adherence in clinical practice. We describe both treatment outcomes and treatment protocol adherence in a retrospective single-center cohort study of pediatric Wilms tumor patients at a zonal cancer referral hospital in Tanzania from 2016 to 2019, treated per the International Society of Paediatric Oncology standard (2016-2017) or Tanzania adapted (2018-2019) therapy protocols. A total of 69 patients were evaluated. The two-year overall survival and event-free survival rates were 40% and 29%, respectively. Only 29% of patients completed recommended chemotherapy per protocol, and completion of preoperative and postoperative chemotherapy was predictive of two-year overall survival (odds ratio [OR] 14.4, p<.001). There were delays at almost every stage of treatment, especially time from preoperative chemotherapy to surgery (56days), from surgery to pathology report (30days), and from surgery to initiation of postoperative chemotherapy (38days). Nonadherence with recommended Wilms tumor treatment guidelines due to key health system delays correlated to reduced overall survival rates, with chemotherapy nonadherence due to abandonment, lack of surgery, and deaths on therapy as the strongest contributors. Future interventions targeting health system delays and reducing deaths during therapy are critical to improving protocol compliance and increasing overall survival for pediatric Wilms tumor patients in low-resource settings.