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.