Nomogram predicted recurrence-free survival after resection of gastrointestinal stromal tumors

A nomogram or computerized tool that accounted for prognostic criteria, including tumor size, site of origin and mitotic index, had better predictive accuracy for cancer recurrence than two commonly used staging systems.

Researchers conducted a study to establish a nomogram for predicting risk for recurrence after surgical resection of gastrointestinal stromal tumors in patients naive to imatinib (Gleevec, Novartis). Although treatment with imatinib has been shown to prolong recurrence-free survival, financial cost and potential toxic effects highlight the importance of calculating recurrence risk, according to researchers.

They developed the nomogram based on 127 patients treated at Memorial Sloan-Kettering Cancer Center and validated the tool based on 212 patients from the Spanish Group for Research on Sarcomas and 148 patients from the Mayo Clinic.

They calculated concordance probability and compared the predictive ability of the device with that of staging systems, including the NIH-Fletcher model, the NIH-Miettinen model and the recently updated Armed Forces Institute of Pathology-Miettinen model.

Concordance probability was 0.78 in the Memorial Sloan-Kettering Cancer Center group. In the Spanish Group for Research on Sarcomas, concordance probability was better for the nomogram (0.76) than for the NIH-Fletcher (0.70; P=.04) and the NIH-Miettinen (0.66; P=.01) models.

In the Mayo Clinic group, concordance probability was 0.80 for the nomogram vs. 0.74 for the NIH-Fletcher model (P=.04) and 0.78 for the NIH-Miettinen model (P=.05). The nomogram had higher concordance probability than the AFIP-Miettinen model, although the findings were not statistically significant.

Predictions of recurrence-free survival at two years and five years with the nomogram appeared to be well calibrated with actual recurrence-free survival in both validation groups.

“The nomogram might be useful for patient care, interpretation of clinical trial results and selection of patients for adjuvant imatinib therapy,” the researchers said.

Gold JS. Lancet Oncol. 2009;doi:10.1016/S1470-2045(09)70242-6.