title: Tumour thickness and relationship to locoregional failure in cancer of the buccal mucosa.
abstract: OBJECTIVE
  The TNM system is the main parameter in treatment planning and the prediction of survival in oral cancer. Here, we investigate the role of tumour thickness as a predictor of locoregional failure and survival in node-negative patients.
  
  
  METHODS
  We studied 176 node-negative and early stage gingivo-buccal squamous cell carcinoma patients retrospectively. Clinico-pathological factors investigated for tumour failure prediction were: T stage; tumour differentiation; tumour thickness; and treatment. Tumour thickness was measured using an ocular micrometer.
  
  
  RESULTS
  Locoregional tumour failure was found in 34% of cases (60 of 176). Tumour differentiation was found not to be statistically significant in predicting tumour failure. The covariates predicting tumour failure were T stage (P<0.05); type of surgical treatment (P<0.05); and tumour thickness (P<0.001). The mean tumour thickness found was 4 mm. Tumours 4 mm in thickness behaved similarly in all three stages and those >4 mm had a higher rate of lymph-node metastasis. No distant metastasis was found in this series.
  
  
  CONCLUSIONS
  Tumour thickness was found to be an accurate predictor of locoregional failure in early stage cancer of the buccal mucosa.
authors.affiliation: Acharya Harihar Regional Cancer Centre, Orissa, India.
authors.forename: R C
authors.initials: RC
authors.lastname: Mishra
authors.forename: G
authors.initials: G
authors.lastname: Parida
authors.forename: T K
authors.initials: TK
authors.lastname: Mishra
authors.forename: S
authors.initials: S
authors.lastname: Mohanty
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000209:etiology / Q000473:pathology*; D016009:Chi-Square Distribution; D018572:Disease-Free Survival; D005887:Gingival Neoplasms / Q000209:etiology / Q000473:pathology*; D006801:Humans; D007194:India; D009061:Mouth Mucosa; D009062:Mouth Neoplasms / Q000209:etiology / Q000473:pathology*; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012189:Retrospective Studies