title: Should severe epithelial dysplasia be treated?
abstract: To identify clinical features associated with progression of primary severe epithelial dysplasia into invasive squamous cell carcinoma (SCC).
  
  
  
  Longitudinal population-based study.
  
  
  
  Oral dysplasia clinics.
  
  
  
  This study involved 118 patients with 118 severe dysplasia who were prospectively enrolled between 1996 and 2014, and the lesions were either completely removed surgically (treated) or actively followed (untreated).
  
  
  
  Demographics, habits, clinical information and outcome were compared between the treated and untreated groups.
  
  
  
  Of the 118 lesions, 77 were treated and 41 were not. The treated lesions showed significantly less progression when compared to the untreated: 5/77 (6%) treated lesions progressed into invasive SCC versus 12/41 (29%) untreated (P=0.004). The 5-year probability (confidence interval) of progression into SCC for the treated was 7.6 (1-14) as compared to 38.6 (16-55) for the untreated. Interestingly the clinical changes at the site of the disease also had strong predictive value for cancer progression. If the site showed no lesion after treatment or after incisional biopsy (40 cases), only 1 (3%) progressed into cancer. If the site showed ever disappearance of the lesion or marked decrease in the size of the lesion to ⩽10mm (29 cases), 4 (15%) progressed. If the site showed lesions with fluctuation in size or persistent in size or marked increase in size (25 cases), 18 (58%) progressed (P<0.001).
  
  
  
  Treatment significantly reduced cancer progression, and phenotypic changes at the site of the disease had significant predictive value for cancer progression.
authors.affiliation: Faculty of Dentistry, The University of British Columbia (BC), 2199 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada; BC Oral Biopsy Service, Department of Laboratory Medicine and Pathology, Vancouver General Hospital, 910 West 10th Avenue, Vancouver, BC V5Z 1M9, Canada; BC Oral Cancer Prevention Program, BC Cancer Agency, Vancouver, BC V5Z 1L3, Canada. Electronic address: lzhang@dentistry.ubc.ca.
authors.forename: Lewei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Faculty of Dentistry, The University of British Columbia (BC), 2199 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada; BC Oral Cancer Prevention Program, BC Cancer Agency, Vancouver, BC V5Z 1L3, Canada. Electronic address: tarineel@gmail.com.
authors.forename: Tarinee
authors.initials: T
authors.lastname: Lubpairee
authors.affiliation: Faculty of Dentistry, The University of British Columbia (BC), 2199 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada; BC Oral Cancer Prevention Program, BC Cancer Agency, Vancouver, BC V5Z 1L3, Canada. Electronic address: dlaronde@dentistry.ubc.ca.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Laronde
authors.affiliation: BC Oral Cancer Prevention Program, BC Cancer Agency, Vancouver, BC V5Z 1L3, Canada; School of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada. Electronic address: mrosin@bccrc.ca.
authors.forename: Miriam P
authors.initials: MP
authors.lastname: Rosin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001955:British Columbia; D002294:Carcinoma, Squamous Cell / Q000473:pathology / Q000628:therapy*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000473:pathology / Q000628:therapy*
keywords: Cancer progression; Dysplasia; Oral cancer; Oral premalignant lesions; Treatment