Primary Tumour Volume Delineation in Nasopharyngeal Carcinoma and Correlation with 1997 AJCC Tumour Stage Classification

OBJECTIVE: To investigate the variability in primary tumour volume in nasopharyngeal carcinoma and compare it with the tumour staging of the 1997 American Joint Committee on Cancer. DESIGN: Prospective study. SETTING: Tertiary care centre. METHOD: A series of 33 newly diagnosed patients who were treated with high-dose radiotherapy participated in the study. MAIN OUTCOME MEASURES: Using computed tomographic scans, primary tumour volumes were measured using the summation-of-areas technique, and the variability in tumour volume was determined. The Mann-Whitney test was used for statistical analysis. RESULTS: A large variation in primary tumour volume was observed, especially in advanced-stage cases. CONCLUSIONS: Nasopharyngeal carcinoma shows considerable variability in primary tumour volume. Incorporation of primary tumour volume may lead to further refinement of the 1997 tumour staging system.