Significance of tumour volume measurements in tongue cancer: A novel role in staging

Background: Tongue cancers are staged by the American Joint Committee on Cancer and the Union Internationale Contre le Cancer TNM staging systems. Cancer, however, evolves in a 3-D plane. Hence, using the largest tumour diameter will not reflect total cancer volume. We aim to evaluate the use of tongue cancer tumour volume (Tv) as a prognostic predictor of disease recurrence and survival. Methods: The study is a retrospective analysis of patients in Singapore General Hospital who underwent complete resection for histologically proven tongue carcinoma from 2000 to 2002. The Tv was measured on staging T-2-weighted magnetic resonance imaging datasets by semiautomated methods. Results: Seventeen patients with a median follow-up duration of 57.9 months were studied. A wide range of volumes was noted in each T stage. The median time to relapse was 8.6 months for those with Tv >= 13 cc but was not achieved for those with Tv < 13 cc. The hazard ratio comparing Tv >= 13 cc versus < 13 cc is 9.02 (95% confidence interval (CI) 1.70-47.94, P = 0.014). Of the seven deaths reported, five patients had Tv >= 13 cc. The median overall survival was 15.8 months for those with Tv >= 13 cc but was not achieved for those with Tv < 13 cc. The hazards of death for Tv >= 13 cc was 3.91 times that of Tv < 13 cc (95%CI 0.86-17.86, P = 0.078). Conclusion: Tongue cancer Tv measurement allows a more refined and accurate assessment of tumour status. This can be a possible prognostic indicator and be used in a novel staging method for the future.