Which classification for ethmoid malignant tumors involving the anterior skull base?

The purpose of this study was to compare three systems of classification for malignant ethmoidal tumors in patients undergoing anterior craniofacial resection.

A radiologic locoregional evaluation of 241 patients with malignant ethmoid tumors was performed before patients underwent an anterior craniofacial resection. Disease in each case was staged according to the American Joint Committee on Cancer-Union Internationale Contre le Cancer (AJCC-UICC) 1997 classification, the AJCC-UICC 2002 classification, and the Istituto Nazionale Tumori (INT) classification. Kaplan-Meier curves and Cox models were used to investigate the prognostic value of each classification system on disease-free survival (DFS) and overall survival (OS). The classifications were compared in terms of prognostic discrimination capability, measured by use of an index of agreement between each classification and DFS or OS time.

All three classification systems yielded statistically significant results in the Cox analysis, both for DFS and OS. In the AJCC-UICC 2002 system, minor differences were observed between T1 and T3 tumors. The INT classification showed a progressive worsening of the prognosis with increasing stage. The index of prognostic discrimination favored the INT classification over both the 1997 and 2002 AJCC-UICC classifications.

Both the 1997 and 2002 AJCC-UICC classifications seemed to have limited prognostic value. By contrast, the INT classification satisfied one of the main goals of tumor staging, demonstrating the progressive worsening of prognosis with different tumor classes.