title: Re-excision rates of invasive ductal carcinoma with lobular features compared with invasive ductal carcinomas and invasive lobular carcinomas of the breast.
abstract: BACKGROUND
  Invasive ductal carcinoma (IDC) with lobular features (IDC-L) is not recognized as a subtype of breast cancer. We previously showed that IDC-L may be a variant of IDC with clinicopathological characteristics more similar to invasive lobular carcinoma (ILC). We sought to determine the re-excision rates of IDC-L compared with ILC and IDC, and the feasibility of diagnosing IDC-L on core biopsies.
  
  
  METHODS
  Surgical procedure, multiple tumor foci, tumor size, and residual invasive carcinoma on re-excision were recorded for IDC-L (n = 178), IDC (n = 636), and ILC (n = 251). Re-excision rates were calculated by excluding mastectomy as first procedure cases and including only re-excisions for invasive carcinoma. Slides of correlating core biopsies for IDC-L cases initially diagnosed as IDC were re-reviewed.
  
  
  RESULTS
  For T2 tumors (2.1-5.0 cm), re-excision rates for IDC-L (76 %) and ILC (88 %) were higher than that for IDC (42 %) (p = 0.003). Multiple tumor foci were more common in IDC-L (31 %) and ILC (26 %) than IDC (7 %) (p < 0.0001), which was a significant factor in higher re-excision rates when compared with a single tumor focus (p < 0.001). Ninety-two of 149 patients (62 %) with IDC-L were diagnosed on core biopsies. Of the 44 patients initially diagnosed as IDC, 30 were re-reviewed, of which 24 (80 %) were re-classified as IDC-L.
  
  
  CONCLUSIONS
  Similar to ILC, re-excision rates for IDC-L are higher than IDC for larger tumors. Patients may need to be counseled about the higher likelihood of additional procedures to achieve negative margins. This underscores the importance of distinguishing IDC-L from IDC on core biopsies.
authors: Department of Pathology, University of Michigan Health System, Ann Arbor, MI, USA.
authors: David P
authors: DP
authors: Arps
authors: Julie M
authors: JM
authors: Jorns
authors: Lili
authors: L
authors: Zhao
authors: Jessica
authors: J
authors: Bensenhaver
authors: Celina G
authors: CG
authors: Kleer
authors: Judy C
authors: JC
authors: Pang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D062005:Biopsy, Large-Core Needle; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000601:surgery*; D018275:Carcinoma, Lobular / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008408:Mastectomy / Q000379:methods; D015412:Mastectomy, Segmental; D008824:Michigan; D008875:Middle Aged; D009367:Neoplasm Staging; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D016896:Treatment Outcome