title: Factors predicting poor outcomes in T1N0 oral squamous cell carcinoma: indicators for treatment intensification.
abstract: BACKGROUND
  This study investigated the impact of adverse pathological features (APFs) amongst patients with T1N0 oral squamous cell carcinoma (OSCC) on both tumour control and survival. We aimed to investigate clinicopathological factors that would predict poor outcomes and determine a clinically relevant threshold for the recommendation of additional treatment.
  
  
  METHODS
  Retrospective analysis of 121 patients from a single institution (1988-2013) who were treated with surgery only (wide local excision of the primary tumour with or without neck dissection). Only patients who are pT1cN0 or pT1pN0 were included. Patients who had received adjuvant radiotherapy were excluded from the study.
  
  
  RESULTS
  APFs were associated with increased regional failure included tumour thickness (TT) ≥5 mm (P = 0.007), perineural invasion (PNI) (P = 0.003), infiltrative border (P = 0.030) and poor differentiation (P = 0.005). Poorly differentiated tumours were also associated with increased local failure (P = 0.03). Local control (LC), regional control (RC) and disease-specific survival (DSS) decreased with an increasing number of APFs (P = 0.009, P = <0.001 and P = 0.009, respectively). Patients with four or more APFs had significantly worse outcomes in LC (P < 0.001), RC (P < 0.001) and DSS (P < 0.001).
  
  
  CONCLUSIONS
  T1N0 OSCC exhibiting four or more APFs or demonstrating poor differentiation on histology had an increased risk of locoregional failure. The presence of PNI, infiltrative border and TT ≥5 mm are associated with increased regional failure. These factors may prompt escalation of treatment for patients with T1N0 OSCC.
authors.affiliation: Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.|Department of Otolaryngology Head and Neck, Victoria Hospital, London, Ontario, Canada.
authors.forename: Tsu-Hui Hubert
authors.initials: TH
authors.lastname: Low
authors.affiliation: Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.
authors.forename: Kan
authors.initials: K
authors.lastname: Gao
authors.affiliation: Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia.|Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Ruta
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.
authors.forename: Anthony
authors.initials: A
authors.lastname: Clifford
authors.affiliation: Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.|Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Elliott
authors.affiliation: Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.|Institute of Academic Surgery at Royal Prince Alfred Hospital, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Sydney
authors.initials: S
authors.lastname: Ch'ng
authors.affiliation: Department of Radiation Oncology, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: Milross
authors.affiliation: Sydney Head and Neck Cancer Institute, Chris O'Brien Lifehouse, Sydney, New South Wales, Australia.|Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Clark
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D005260:Female; D005544:Forecasting; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000175:diagnosis / Q000401:mortality / Q000601:surgery*; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology*; D009367:Neoplasm Staging; D009517:New South Wales / Q000453:epidemiology; D019647:Oral Surgical Procedures / Q000379:methods*; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
keywords: AJCC stage; depth of invasion; head and neck cancer; oral cavity squamous cell carcinoma; tumour thickness