The influence of quantitative tumor volume measurements on local control in advanced head and neck cancer using...

Current methods to clinically define head and neck tumor bulk are qualitative and imprecise. Although the American Joint Committee on Cancer (AJCC) staging system is important for this purpose, limitations exist. This study will investigate the prognostic value of computed tomography (CT) derived tumor volume measurements in comparison to AJCC stage and other significant variables.

Seventy-six patients with advanced head and neck squamous cell carcinoma were treated with concomitant boost accelerated superfractionated irradiation. Doses ranged from 68.4-73.8 Gy (median 70.2 Gy). Good quality pretherapy CT scans were available in 51 patients. Total tumor volume (TTV) estimates were derived from these scans using digital integration of primary tumor and metastatic lymphadenopathy. Actuarial and multivariate statistical techniques were applied to analyze local control.

Thirty-six-month local control was 63%. TTV ranged from 5-196 cm3 (median 35 cm3) for all cases, 5-142 cm3 (median 17 cm3) for those controlled, and 16-196 cm3 (median 47 cm3) for local failures. There was a significant increase in failures above 35 cm3. Univariate analysis found that TTV, T-stage, N-stage, and primary site were each significant prognostic variables. Local control for TTV < or = 35 cm3 was 92% at 36 months vs. 34% for TTV > 35 cm3 (p = 0.0001). Multivariate analysis, however, found that TTV, primary site, and sex were important as independent variables; T and N stage were not independently significant unless TTV was removed from the model.

This study demonstrates the prognostic significance of TTV in advanced carcinoma of the head and neck. This variable appears to be a more predictive than AJCC clinical stage. Quantitative tumor volume measurements may prove to be a useful parameter in future analyses of head and neck cancer.