Purpose: The aim of our study was to assess the prognostic value of tumor volume compared to and in addition to T-stage on local control (LC), disease-free survival (DFS), and overall survival (OS) in glottic and supraglottic laryngeal carcinoma patients.
Patients and methods: In 150 patients, we determined tumor volume on diagnostic CT scans. We applied crude and multivariable Cox regression analysis to relate volume (continuous), T-stage and the combination to 5-year DFS, OS, and LC. Before, we examined the linearity assumption of the association between volume and outcome with restricted cubic spline functions. Prognostic performance of the models was examined by determination of the model's discrimination. Discriminative ability was determined with the C statistic referring to the ability to discriminate between patients who do and do not develop an event during follow-up.
Results: A strong association between tumor volume and DFS and OS was found. The restricted cubic spline plot did not indicate a non-linear relationship between tumor volume and DFS and local control. Tumor volume demonstrated a better discriminative ability to predict DFS and OS compared to T-stage (0.68 and 0.57 vs. 0.59 and 0.54, respectively). For local control, T-stage showed a higher discriminative ability than tumor volume (0.63 vs. 0.61). The combined model increased discriminative power (0.69).
Conclusion: Volume seems to be more important than T-stage in prediction of DFS or OS in laryngeal squamous cell carcinoma patients. Perhaps prediction of DFS, OS, and LC could be improved by including tumor volume into the staging process.