New prognostic tool for GIST recurrence

American researchers have developed a new computerised tool that is more accurate than existing models in predicting a patient’s risk of cancer recurrence after surgery to remove primary gastrointestinal stromal tumours (GIST). Using three established prognostic criteria: tumour size, location and mitotic index the researchers used data from 127 patients with primary GIST to predict their recurrence-free survival (RFS) at two and five years after surgery. The tool was then used to observe and predict RFS in 360 GIST patients and the findings were compared with three predictive staging systems currently used in the U.S: US National Institutes of Health (NIH)-Fletcher, NIH-Miettinen, and the recently updated Armed Forces Institute of Pathology (AFIP)-Miettinen. Overall, the tool was better at predicting the likelihood of RFS than the NIH and AFIP staging systems. “Prognostic nomograms give better prediction of the likelihood of events for individual patients than do staging systems that stratify patients into a few broad groups,” the researchers wrote in Lancet Oncology. They noted that tumour size, location and mitotic index are routinely reported by many pathologists, making their model “broadly applicable, useful for patient care and for interpretation of clinical trial results and the selection of patients for adjuvant imatinib therapy”. “We have established a prognostic method to predict RFS for individual patients… that will allow patients to be counselled appropriately regarding their probable outcome… and be selected properly for postoperative treatment,” they said. “Furthermore, physicians can identify the type and frequency of postoperative surveillance for tumour recurrence.” In an accompanying editorial, Heikki Joensuu from Helsinki University Central Hospital in Finland welcomed the new tool, calling it "a step forward in the individualisation of prognostication". The Lancet Oncology doi:10.1016/S1470-2045(09)70242-6...