Importance of tumour thickness measurement in prognosis of tongue cancer.

Eighty-one patients who underwent surgery for cancer of the tongue were retrospectively studied to evaluate the influence on survival of some clinical and pathologic parameters. These parameters and data on the patient's current status were gathered by the study of tissue sections, using haematoxylin-eosin staining, and from medical records. The 5-year survival rate was 68.5%. Univariate analysis showed that the parameters influencing survival were: T (P<0.01), pathologic T (P<0.01), N (P<0.05), pathologic N (P<0.05), extracapsular nodal spread (P<0.05), locoregional recurrence (P<0.01), and tumour thickness (P<0.05). Multivariate analysis showed that tumour thickness had the greatest influence on survival. Patients with tumour thickness of < or = 3 mm had a 5-year survival of 85.7%, significantly greater (P<0.05) than the rates of 58.3 and 57% for patients with tumour thickness of 4-7 mm and >7 mm, respectively. Wider studies are required to unify criteria for the measurement of this important prognostic parameter.