title: Staging significance of bone invasion in small-sized (4cm or less) oral squamous cell carcinoma as defined by the American Joint Committee on Cancer.
abstract: OBJECTIVE
  The staging significance of bone invasion is controversial in oral squamous cell carcinoma (OSCC) cases with tumors measuring 4cm or less according to the American Joint Committee on Cancer (AJCC). Our aim was to retrospectively examine a large group of patients with OSCC to determine the staging significance of bone invasion.
  
  
  METHODS
  Three hundred and twenty-three patients with primary OSCC were classified based on tumor size. Bone invasion was categorized as absent, one side bone, and both buccal and lingual bones, and analyzed for association with disease progression. Regional lymph node metastasis (N), perineural invasion, vascular invasion, surgical margin involvement, and adjuvant treatment were also analyzed.
  
  
  RESULTS
  In all OSCC cases, bone invasion (p=0.007) with stage N, perineural invasion, and surgical margin involvement were significant independent prognostic factors of disease progression. However, in OSCC cases with tumors measuring 4cm or less, bone invasion was not significantly associated with disease progression. Nevertheless, invasion of both buccal and lingual bones was significantly associated with disease progression (p=0.03). In multivariate analysis, both buccal and lingual bone invasion (p=0.04; hazard ratio=3.4; 95% confidence interval, 1.0-11.0), stage N2, and perineural invasion were also independent prognostic factors.
  
  
  CONCLUSIONS
  Although OSCC bone invasion was an independent prognostic factor, bone invasion in small OSCC was not. However, small OSCC with both buccal and lingual bone invasion had a significantly worse prognosis. The AJCC T system is of limited prognostic value for small OSCC with bone invasion. But other elements should be examined before a modification can be accepted.
authors.affiliation: Department of Oral Pathology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Su Kyung
authors.initials: SK
authors.lastname: Kuk
authors.affiliation: Department of Oral Pathology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Hye Jung
authors.initials: HJ
authors.lastname: Yoon
authors.affiliation: Department of Oral Pathology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Seong Doo
authors.initials: SD
authors.lastname: Hong
authors.affiliation: Department of Oral Pathology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea.
authors.forename: Sam Pyo
authors.initials: SP
authors.lastname: Hong
authors.affiliation: Department of Oral Pathology, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea. Electronic address: jilee@snu.ac.kr.
authors.forename: Jae Il
authors.initials: JI
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000556:secondary*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007568:Jaw / Q000473:pathology*; D007573:Jaw Neoplasms / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D055815:Young Adult
keywords: Bone invasion; Disease progression; Head and neck cancer; Oral cancer; Prognosis; Squamous cell carcinoma; Staging