METHODS
The study is a retrospective analysis of all patients diagnosed with Wilms tumor in KOH between April 2005 and December 2014. A total of 177 patients are registered as Wilms tumor. Thirty-four patients are excluded from the study because the information is incomplete.
Details of presentation, histology, and management were extracted from patient records. All patients were staged radiographically with chest and abdomen CT and during surgery. The national Wilms tumor study group (NWTSG) is used for staging (5). Patients are divided into two main groups. The first group is patients who completed treatment (chemotherapy surgery and radiotherapy), and the rest did not start or did not complete treatment. Standard practice throughout this period was that patients were assessed at diagnosis by the pediatric surgeon outside the center. Primary surgery was undertaken where possible. For tumors considered inoperable, pre-operative chemotherapy was given after Tru cut biopsy. These tumors were regarded as stage III. The histopathology was reviewed at different labs and by a different pathologist. Chemotherapy and radiotherapy are started as soon as possible. Since surgery and the pathology review were done outside the center, there was a considerable delay in starting treatment promptly. Chemotherapy was delivered according to NWTSG IV (5) Relapses were treated with surgery if local only, followed by chemotherapy. Surgical removal of the liver and pulmonary metastasectomy is not available and were treated with chemotherapy only. Radiotherapy for lung and liver metastases is technically not possible. Radiation is given to local relapses if not given initially. The relapse chemotherapy regimens used include vincristine, actinomycin, doxorubicin, cyclophosphamide, ifosfamide, etoposide, and carboplatin.
Outcome at the end of treatment was categorized as (a) alive without evidence of disease, (b) treatment abandonment, (c) death from disease persistent disease (unresectable disease, relapse of disease, or persistent disease after the completion of the full treatment), or (e) death from treatment side effect. Relapse patients who achieved a complete response after second-line treatment are considered as group (a). Survival time was calculated from diagnosis to the last moment of contact, either by clinic visit or active follow up.
The event was defined as no treatment initiated, incomplete treatment, and death. OS and event-free survival are estimated using the Kaplan-Meier and Log-rank test by SPSS 24.