title: Does the volume of ductal carcinoma in situ impact the positive margin rate in patients undergoing breast conservation for invasive breast cancer?
abstract: BACKGROUND
  We sought to investigate whether the volume of ductal carcinoma in situ (DCIS) impacts margin status in patients undergoing lumpectomy for invasive breast cancer.
  
  
  METHODS
  We identified 358 patients with stages I-III invasive breast cancer and associated DCIS who were treated with breast-conserving therapy from 1999 to 2009. Data included patient and tumor characteristics, percentage of DCIS (<25%, 26%-50%, or >50%), and pathologic outcomes. Data were compared using chi-square and Fisher exact tests. A two-tailed P value of <0.05 was considered significant.
  
  
  RESULTS
  The 358 patients had a mean age of 58 ± 13 y; 260 (72%) patients were >50 y. The volume of DCIS in lumpectomy specimens was <25% in 296 (83%) patients, 26%-50% in 29 (8%) patients, and >50% in 33 (9%) patients. Tumors with decreasing DCIS volume were more likely to be estrogen receptor positive (239 [82%] with <25% DCIS, 21 [72%] with 26%-50% DCIS, 22 [67%] with >50% DCIS; P=0.026). DCIS volume was not significantly associated with patient age, tumor size, grade, and stage, nodal status, progesterone receptor status, or Her2 status (P>0.05). Overall, 137 (38%) patients had one or more positive margins, including 97 of 296 (33%) with <25% DCIS volume, 17 of 29 (59%) with 26%-50% DCIS volume, and 23 of 33 (70%) with >50% DCIS volume (P<0.0001).
  
  
  CONCLUSIONS
  The volume of DCIS associated with an invasive breast cancer in the final lumpectomy specimen is a strong predictor of positive surgical margins. Future analyses will focus on the ability of core pathology to provide this information for intraoperative surgical decision making.
authors.affiliation: Department of Surgery, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
authors.forename: Tonya M
authors.initials: TM
authors.lastname: Martin-Dunlap
authors.forename: Amy E
authors.initials: AE
authors.lastname: Cyr
authors.forename: Fatema
authors.initials: F
authors.lastname: Al Mushawah
authors.forename: Feng
authors.initials: F
authors.lastname: Gao
authors.forename: Julie A
authors.initials: JA
authors.lastname: Margenthaler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D002278:Carcinoma in Situ / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology / Q000473:pathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D018365:Neoplasm, Residual / Q000453:epidemiology / Q000473:pathology / Q000601:surgery; D012189:Retrospective Studies; D012307:Risk Factors; D047368:Tumor Burden
keywords: Breast cancer; Breast conservation; Ductal carcinoma in situ; Margins