EVALUATION OF THE CLINICAL TNM STAGING SYSTEM FOR MALIGNANT PLEURAL MESOTHELIOMA - AN ASSESSMENT IN 88 PATIENTS

There is no universally-recognised method for staging malignant mesoth elioma, although the use of computed tomograph (CT) scanning has impro ved the staging of non-invasive disease, The International Union again st Cancer has recently proposed using the Tumour Node Metastases (TNM) staging system for mesothelioma, but in clinical practice it is diffi cult to assess tumour and nodal involvement due to the unique plate-li ke growth pattern of this tumour. In order to evaluate TNM staging we analysed pre-operative CT scans from 88 patients with histologically-c onfirmed malignant pleural mesothelioma, all from the same institution . The median age of the patients was 56 years (range 38-79). There wer e 70 men and 18 women, and 33 had tumours with epithelial histology. T he median survival time was 10 months (range 0.2-110), from the date o f histological confirmation of mesothelioma. The same radiologist anal ysed all the CT scans according to the TNM staging system, Actuarial s urvival curves were constructed by the Kaplan-Meier method. Survival c urves for the different TNM categories were compared using the log-ran k test. Node evaluation could not be completed in eight cases because the tumour had encompassed the hilum and mediastinum. In multivariate analysis, significant differences in prognosis correlated with the dif ferent T categories (P < 0.01), and the different TNM stages (P < 0.05 ), but not the N categories or the M categories. Larger studies are ne eded to assess the importance of TNM staging in the selection of treat ment and as a prognostic factor for malignant mesothelioma.