Impact Of Prolonged Duration Of Pre-operative Chemotherapy For Unilateral Wilms Tumor In Blantyre, Malawi: A Five Year Experience

Globally, 90% of Wilms tumors are cured using a combination of chemotherapy, surgery, and radiotherapy despite the use of different treatment guidelines. Patients with unilateral WT treated using the International Society of Paediatric Oncology (SIOP) guidelines are offered preoperative chemotherapy for 4 weeks to reduce tumor size and risk of rupture during surgery which allows less postoperative chemotherapy and less radiotherapy. Paediatric Oncology in Developing Countries (PODC), part of SIOP, proposed a prolonged duration of pre-operative chemotherapy in attempt and data from Malawi has shown extended periods of preoperative chemotherapy up to 12 weeks for unilateral WT. Prolonging the duration of preoperative chemotherapy in unilateral tumours can reduce tumour size further yet an effective extended duration of preoperative chemotherapy in this settings is unknown. This study aimed to determine an effective duration to administer preoperative chemotherapy in a low resource setting that allows for a high event free survival and overall survival. Data from 44 paediatric patients with unilateral and localised Wilms tumor treated between 2015-2020 at Queen Elizabeth Central Hospital was analyzed retrospectively to assess relapse-free interval and overall survival rate at 24 months. Our findings show that prolonging the duration of preoperative chemotherapy beyond 8 weeks did not have any added advantage to the risk of local and distant relapse as well as the overall survival rate. Local relapse increased with 38.2% for each additional week beyond 8 weeks with a p-value of 0.052 (95% CI [0.82, 2.16]). Limitation to our study was the small sample size, therefore multi-centre and large studies are needed to influence the treatment guidelines in the region.