Gastric GIST and prognostic models. Which is the best to predict survival after surgery?

Background: Gastrointestinal Stromal Tumours (GIST) are the most frequent mesenchymal tumour of the alimentary tract. Their prognosis is largely variable as are their size, mitotic rate and site, the stomach being mostly affected. Several risk classifications have been proposed: two developed by the NIH, one proposed by the AFIP and one presented by the AJCC in 2010.