title: Importance of Surgical Margin Status in Ductal Carcinoma In Situ.
abstract: The purpose of the study was to identify the effect of final surgical margin (SM) status and re-excision on outcomes in patients with ductal carcinoma in situ (DCIS) who underwent breast conservation therapy (BCT).
  
  
  
  The study population consisted of women diagnosed with DCIS who underwent BCT between 1989 and 2014. All women received adjuvant whole breast radiation and a boost. The primary end point was local control (LC). Final SMs were defined according to margin width: negative SM was defined as > 2 mm, close SM was defined as > 0 to ≤ 2 mm, and a positive SM was defined as tumor on ink. The Cox proportional hazards model was used to determine predictors of outcomes on multivariable analysis. Actuarial incidence of LC was estimated using the Kaplan-Meier method.
  
  
  
  A total of 498 patients were included; 400 patients had a final negative SM, 87 had a close SM, and 11 had a positive SM. A total of 172 patients received adjuvant hormonal therapy, 265 patients required ≥ 1 re-excision. Patients with positive or close SMs were more likely to receive a radiation dose > 60 Gy (P < .001) and undergo re-excision (P < .01). The 10-year LC rates were not significantly different between patients with a negative (93.5%), close (91.8%), or positive (100%) SM (P = .57). There was no difference in LC in patients who underwent re-excision for initial close or positive SMs (P = .55).
  
  
  
  This single-institution experience showed that risks of local recurrence remain poorly characterized. Re-excision and whole breast radiation with boost resulted in excellent LC for women with DCIS. Trials aimed at personalized deintensified local therapy are warranted.
authors.affiliation: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Talha
authors.initials: T
authors.lastname: Shaikh
authors.affiliation: Department of Biostatistics, Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Tianyu
authors.initials: T
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Colin T
authors.initials: CT
authors.lastname: Murphy
authors.affiliation: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Zaorsky
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Bleicher
authors.affiliation: Department of Surgical Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Elin R
authors.initials: ER
authors.lastname: Sigurdson
authors.affiliation: Department of Medical Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Robert
authors.initials: R
authors.lastname: Carlson
authors.affiliation: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA.
authors.forename: Shelly B
authors.initials: SB
authors.lastname: Hayes
authors.affiliation: Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA. Electronic address: penny.anderson@fccc.edu.
authors.forename: Penny
authors.initials: P
authors.lastname: Anderson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D000072662:Margins of Excision; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant / Q000379:methods; D012086:Reoperation; D016896:Treatment Outcome
keywords: Boost; Breast conservation; DCIS; Hormonal therapy; Re-excision