title: Differential Impact of Close Surgical Margin on Local Recurrence According to Primary Tumor Size in Oral Squamous Cell Carcinoma.
abstract: BACKGROUND
  The extent of surgical safety margin (gross tumor border to resection margin) in oral cancer surgery remains unclear, and no study has determined the differential impact of close surgical margin and microscopic extension according to primary tumor size in oral cancers.
  
  
  METHODS
  We retrospectively analyzed the clinical data of 325 patients with surgically treated oral cavity squamous cell carcinomas to determine the effect of a close surgical margin (<5 mm) (cSM5) on local recurrence. In addition, the depth of microscopic tumor infiltration was determined in 90 available surgical specimens.
  
  
  RESULTS
  The cSM5was not related to the risk of local tumor recurrence in early-stage oral cancer, while it significantly increased the rate of local tumor recurrence in resectable advanced-stage oral cancers (hazard ratio 3.157, 95 % confidence interval 1.050-9.407, p = 0.041). Addition of postoperative adjuvant radiation to early-stage tumors with cSM5did not further reduce the local recurrence rate compared to surgery alone. The depth of microscopic tumor extension from the gross tumor border was significantly associated with primary tumor thickness (ρ = 0.390, p < 0.001) and tumor sizes (ρ = 0.308, p = 0.003), which was a median (range) of 0.84 (0.14-2.32) mm in T1, 1.06 (0.20-4.34) mm in T2, and 1.77 (0.13-4.70) mm in T3-4.
  
  
  CONCLUSIONS
  The cSM5was a significant risk factor for local recurrence only in advanced oral cancers, but not in early-stage tumors, where microscopic tumor extension was not beyond 3 mm in T1 tumors. Thus, the extent of surgical safety margin can be redefined according to the primary tumor size.
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Biomedical Research Institute, Pusan National University Hospital, Pusan National University School of Medicine, Busan, Republic of Korea.
authors: Jeon Yeob
authors: JY
authors: Jang
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Nayeon
authors: N
authors: Choi
authors: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Young-Hyeh
authors: YH
authors: Ko
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Man Ki
authors: MK
authors: Chung
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Young-Ik
authors: YI
authors: Son
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors: Chung-Hwan
authors: CH
authors: Baek
authors: Department of Molecular and Cellular Biology, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine,Suwon, Gyeonggi, Republic of Korea.
authors: Kwan-Hyuck
authors: KH
authors: Baek
authors: Department of Otorhinolaryngology-Head and Neck Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. hansin.jeong@gmail.com.
authors: Han-Sin
authors: HS
authors: Jeong
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D009062:Mouth Neoplasms / Q000473:pathology* / Q000601:surgery; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery; D018365:Neoplasm, Residual / Q000473:pathology* / Q000601:surgery; D011379:Prognosis; D012189:Retrospective Studies; D015996:Survival Rate