Gastrointestinal stromal tumours in children and young adults: a clinicopathologic series with long-term follow-up from the database of the Cooperative Weichteilsarkom Studiengruppe (CWS).

Studies on gastrointestinal stromal tumours (GIST) in the paediatric population are limited to case reports or small case series.We conducted a retrospective study to describe the long-term outcome of children and adolescents with GIST registered in the database of the Cooperative Weichteilsarkom Studiengruppe (CWS).Sixteen patients (female, n = 11) were identified. Median age at diagnosis was 13.5 years. In four female patients presence of thoracic masses in addition to GIST led to the diagnosis of complete or incomplete Carney triad. Three female patients had metastatic disease at diagnosis, the remaining thirteen GIST were localised. The stomach was the most common primary site of the tumour, followed by the small bowel and colon/abdomen. All patients underwent tumour resection. Receptor tyrosine kinase inhibitors (RTKI) were administered in five patients. With a median follow-up of 96 months all patients are alive, nine of them in first CR. Four female patients developed local or distant recurrence; three of them achieved second CR and one a PR. Two individuals have extensive progressive (n = 1) or stable (n = 1) disease. Estimated progression-free survival at 5 years is 0.63 (95%CI: 0.50-0.86).Although long-term overall survival is favourable, approximately 30 percent of patients develop disease progression. International cooperation in registration, tissue collection and molecular studies are required to obtain reliable data on the clinical course of these rare tumours in the paediatric population. Biological studies are a prerequisite for initiation of studies with RTKI.