title: Discordance between pathologic and radiologic tumor size on breast MRI may contribute to increased re-excision rates.
abstract: Preoperative breast MRI does not decrease re-excision rates in patients who undergo lumpectomy. We evaluated concordance of tumor size on MRI and pathologic size in patients who underwent re-excision of margins after lumpectomy. A retrospective review of patients at the Cedars-Sinai  Breast Center who received breast MRI was performed. We found that MRI was performed before lumpectomy in 136 patients. Mean age was 55.2 years (standard deviation ± 12.6). Re-excision occurred in 34 per cent (n = 46). Of those undergoing re-excision, 35 per cent (16/46) were re-excised  for ductal carcinoma in situ (DCIS) at the lumpectomy margin. There was no significant difference between radiologic and pathologic size of the tumor (1.94 vs 2.12 cm; P = 0.159). In those who underwent re-excision, the radiologic size was underestimated compared with  the pathologic size (2.01 vs 2.66 cm; P = 0.032). Patients with pure DCIS lesions (n = 9) also had smaller radiologic tumor size compared with pathologic (0.64 vs 2.88 cm; P = 0.039), and this difference trended toward significance in those who underwent re-excision  (0.55 vs 3.50 cm; P = 0.059). Discordance between tumor size on MRI and pathologic size may contribute to re-excisions in patients who undergo lumpectomy. The limitations of breast MRI to evaluate the extent of DCIS surrounding many breast cancers, and the impact on re-excision  rates, should be further evaluated.
authors: Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, California, USA. lv@drvanderwalde.com
authors: Lindi H
authors: LH
authors: Vanderwalde
authors: Catherine M
authors: CM
authors: Dang
authors: Catherine
authors: C
authors: Bresee
authors: Edward H
authors: EH
authors: Phillips
mesh_terms: D001707:Biopsy, Needle / Q000379:methods*; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015412:Mastectomy, Segmental / Q000379:methods*; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000601:surgery; D009367:Neoplasm Staging / Q000379:methods*; D018365:Neoplasm, Residual / Q000473:pathology / Q000601:surgery; D012086:Reoperation / Q000639:trends*; D012189:Retrospective Studies; D013997:Time Factors