Rare Malignant Tumors in Mexican Pediatric Patients: A Cooperative Pediatric Oncology Research Group Report

Background: Rare malignant tumors (RMT) make up 10% of all cancer in the pediatric age. The national and international cooperative projects will allow to understand their biology and improve the treatment results, making imperative the acknowledge the clinical course and the prognosis of Mexican pediatric patients with (RMT) Results: 178 patients were evaluated, with the age of 3 months to 17 years, 58% adolescents. The symptomatic presentation lag time was 7 days to 2 years. Most frequent symptoms were pain and palpable mass. The predominant histological type was thyroid carcinoma (29%) followed by 9% non-germ gonadal tumors and pancreatic exocrine tumors (6%). 27% metastatic. The treatment was surgical in 88%of the cases, and 5% received only palliative care. There were 38 patients with progression and 12 were due to toxicity. 18.9% of patients were lost of follow up due to abandonment of hospital care or transfer to adult hospital. Overall survival (OS) for all RMT was 63% at 100 months. SG for thyroid carcinomas was 68% within 109 months. Conclusion: The systematic study of RMT is not possible. Patients are staged and treated with protocols designed for adults. In our series, surgery is the cornerstone of treatment. Age establishes an organizational barrier for the treatment and follow-up of these patients in our country. Nevertheless we have taken the first step for this challenge in our country by assembling the first cooperative group of rare tumors, which hopes to become a support in the clinical decisions of pediatric oncologists in Mexico.