title: Prognostic significance of invasion depth in oral tongue squamous cell carcinoma.
abstract: OBJECTIVE
  Staging for tongue carcinoma does not consider its depth of invasion. We aim to determine the prognostic significance of invasion depth in tongue cancer.
  
  
  METHODS
  Retrospective review of patients with tongue carcinoma who underwent curative surgery between 2002 and 2005; 67 patients were analyzed. Tumors were divided into 2 groups: group A = invasion depth <4 mm; group B = invasion depth ≥4 mm. Recurrence and survival rates were calculated for each group and compared.
  
  
  RESULTS
  The local recurrence rate in group B was significantly higher (10 vs. 29.7%, p = 0.048). Group A patients had a superior 5-year overall survival (68.8 vs. 41.6%, p = 0.012), disease-specific survival (67.1 vs. 41.1%, p = 0.026) and local recurrence-free survival (89.5 vs. 65.4%, p = 0.035). Five-year regional recurrence, locoregional recurrence and distant recurrence-free survival rates were not significantly different between the 2 groups (p = 0.390, p = 0.173 and p = 0.207). The impact of invasion depth on survival was maintained on multivariate analysis (p = 0.031).
  
  
  CONCLUSIONS
  Invasion depth is an important prognostic indicator in tongue cancer.
authors.affiliation: Department of Surgical Oncology, National Cancer Centre Singapore, Singapore.
authors.forename: Winson Jianhong
authors.initials: WJ
authors.lastname: Tan
authors.forename: Claramae Shulyn
authors.initials: CS
authors.lastname: Chia
authors.forename: Hiang Khoon
authors.initials: HK
authors.lastname: Tan
authors.forename: Khee-Chee
authors.initials: KC
authors.lastname: Soo
authors.forename: N Gopalakrishna
authors.initials: NG
authors.lastname: Iyer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D005260:Female; D005927:Glossectomy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate; D014062:Tongue Neoplasms / Q000401:mortality / Q000473:pathology* / Q000601:surgery; D055815:Young Adult