title: The Association Between Excision Margins and Local Recurrence in 11,290 Thin (T1) Primary Cutaneous Melanomas: A Case-Control Study.
abstract: BACKGROUND
  At presentation, most primary cutaneous melanomas are "thin" (Breslow thickness ≤1 mm, designated T1 in the American Joint Committee on Cancer staging system) and local recurrence (LR) is rare. Most current management guidelines recommend 1 cm surgical excision margins for T1 melanomas, but evidence to support this recommendation is sparse. We sought to identify clinical and pathologic factors associated with LR in patients with T1 melanomas that might guide primary tumor management.
  
  
  METHODS
  From a large, prospectively collected, single-institution database, patients with primary cutaneous melanomas ≤1 mm thick diagnosed between 1970 and 2011 who developed LR were identified and matched with controls. Clinical and pathologic parameters were analyzed for their association with LR.
  
  
  RESULTS
  From 11,290 primary melanomas ≤1 mm thick, 176 (1.56 %) cases with LR were identified and 176 controls (without LR) were selected. LR occurred after a median time of 37 months (range 3-306 months) and was associated with narrower excision margins (hazard ratio = 0.95, 95 % confidence interval 0.92-0.98, p = 0.001), desmoplastic, acral, and lentigo maligna melanoma subtypes (p = 0.008), and melanomas composed predominantly of spindle cells (p = 0.005). However, Breslow thickness, Clark level, ulceration, mitotic rate, regression, and lymphovascular invasion were not.
  
  
  CONCLUSIONS
  LR was associated with <8 mm histologic excision margins (corresponding to <1 cm margins in vivo) and desmoplastic, acral, and lentigo maligna melanoma subtypes. This study provides evidence that a ≥1 cm clinical excision margin for thin (T1) primary melanomas reduces the risk of LR.
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia.|Department of Plastic Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK.
authors.forename: Alastair D
authors.initials: AD
authors.lastname: MacKenzie Ross
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia.|Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Haydu
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia.|Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.|Department of Melanoma and Surgical Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Quinn
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia.|Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.|Department of Melanoma and Surgical Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Robyn P M
authors.initials: RP
authors.lastname: Saw
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia.|Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.|Department of Melanoma and Surgical Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Kerwin F
authors.initials: KF
authors.lastname: Shannon
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia.|Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Spillane
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia.|Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.|Department of Melanoma and Surgical Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Stretch
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia.|Sydney Medical School, The University of Sydney, Sydney, NSW, Australia.|Department of Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Scolyer
authors.affiliation: Melanoma Institute Australia, North Sydney, NSW, Australia. john.thompson@melanoma.org.au.|Sydney Medical School, The University of Sydney, Sydney, NSW, Australia. john.thompson@melanoma.org.au.|Department of Melanoma and Surgical Oncology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia. john.thompson@melanoma.org.au.
authors.forename: John F
authors.initials: JF
authors.lastname: Thompson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008545:Melanoma / Q000473:pathology* / Q000601:surgery; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000473:pathology* / Q000601:surgery; D009367:Neoplasm Staging; D011379:Prognosis; D011446:Prospective Studies; D012878:Skin Neoplasms / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate; D055815:Young Adult; D000096142:Cutaneous Malignant Melanoma