Retrospective examination of demographic and clinical characteristics, treatment results and side effects of patients diagnosed with Wilms tumor

Background: Wilms tumor is the most common malignant renal tumor of childhood. Treatment of the disease consists of surgery, chemotherapy and, in some cases, radiotherapy. Survival is over 90% with the development of treatment methods. Side effects may occur in patients depending on both the renal parenchyma loss caused by the surgical treatment and the treatments given. Objective: This study aimed to retrospectively examine the demographic and clinical characteristics, treatment results and side effects of patients with Wilms tumor. Methods: 89 patients diagnosed with Wilms tumor and treated at Akdeniz University Faculty of Medicine Hospital, Department of Pediatric Hematology and Oncology between 1 January 1998 and 31 December 2023 were examined in terms of their age at diagnosis, gender, admission complaints, physical examination findings, diagnostic methods, laboratory findings, surgical methods, tumor histology, disease stages, treatments given, relapse status, relapse time, side effects and survival times. During the follow-up of the patients, echocardiography results, proteinuria and hypertension status were evaluated at regular intervals. At the last follow-up, the GFR of the patients was calculated according to their height and creatinine values. Results: 45 (50.6%) of the patients were female and 44 (49.4%) were male. Male/Female ratio found 1/1.02. The median age at diagnosis was 3 years (0,4 years-12.6 years) and the average age at diagnosis was 3.1± 2.1 years. 50.6% of the patients had abdominal distension, 29.2% had nausea/vomiting/abdominal pain, and 24.7% had blood in the urine. The rate of accompanying genetic anomalies was 3.3% (2 cases of Denys Drash syndrome, one case of isolated hemihypertrophy). The bilateral WT rate was 5.6%. 88.8% of the patients were diagnosed by nephrectomy and 11.2% by biopsy. The most common site of metastasis was the lungs. Anaplasia (focal/diffuse) was detected in 11.2%. Preoperative chemotherapy was administered to 39.3% of the patients. Thirty-six patients were treated according to the TPOG WT protocol, and 53 patients were treated according to the NWTS/COG protocol. Radiotherapy was applied to 44.9% of the patients. The relapse rate was 16.9% and the median relapse time was nine months. The median follow-up period was 76 months. Five-year GHY was 88.2% and OYH was 80.5%. During follow-up, proteinuria was detected in 6.7% and hypertension was detected in 4.5% of the patients. At the last follow-up, GFR was <60 ml/min/1.73 m² in 4.5% of the patients. 3.8% of the patients had impaired ventricular function (EF: <30%), and 13.2% had borderline ventricular function (EF: 55-59% and/or PK: 30-34%). Secondary malignancy (leukemia) was observed in one patient. Conclusion: The clinical characteristics and treatment results of the WT patients in this series are similar to the literature. It is especially important to treat patients in centers with teams experienced in tumor surgery. Patients should be closely monitored for long-term side effects. Keywords: Wilms tumor, GFR, renal functions, pre-operative chemotherapy, nephrectomy