[307] Mastectomy Offers the Most Effective Local Surgical Control for Ductal Carcinoma In Situ (DCIS)

K Subik, JM Wang, A Chen, P Ding, P Tai, H Zhang, K Skinner, DG Hicks, P Tang. University of Rochester Medical Center, Rochester, NY; RTI Health Solution, Research Triangle Park, NC

Background: Successful breast-conserving therapy for DCIS is limited by high rates of residual disease and the need for radiotherapy and/or re-excision for better local disease control. This study aimed to identify clinical, surgical, and pathological factors associated with negative surgical margin in re-excised breast specimens.
Design: Forty-seven pure DCIS cases with 2 or more surgical resections were selected from the files of the Department of Pathology. All caes had local resection as the first procedure except for 2 cases with simple mastectomy. All had at least one positive or close (<1mm) margin in the first surgical specimens. 44 cases had 2 procedures, 2 cases had three, and 1 case had four. Clinical and pathological informations including patients' age, grossly identifiable lesion, tumor size, tumor grade, ER and PR status, background proliferative changes (ADH and DH), and time intervals between the first and last surgical procedures were reviewed and analyzed.
Results: Among the 47 cases at the last surgical specimens (17 mastectomies and 30 local re-excisions), only 5 did not show residual DCIS and 19 archived negative margin (>10 mm or no tumor in the specimen). For the rest of the 23 cases, 7 had positive margin (tumor on inked), 8 had close margin (< or = 1 mm), 7 had near margin (>1, but < or =3 mm), and one had a 4 mm margin. Mastectomy was most effective in predicting negative margins (94.12%) compared to local re-excision (30%) in both univariate (p<0.0001) and multivariate (p=0.0053) analysis. The time intervals between the initial and last procedures also seem to be critical for margin control (p=0.0173) in univariate analysis, with a longer interval associated with negative margin. Also, the presence of a grossly identifiable lesion was associated with better margin control (100% vs. 42.62%, p=0.0518). Other factors including age, tumor size, nuclear grades, ER and PR status, and background proliferative changes (ADH and DH) did not affect the margin status.
Conclusions: The majority of the re-excision specimens for DCIS with close margins will have residual disease. Mastectomy, intervals between first and last surgery, and gross mass lesions are most important predictive factors for negative margins.
Category: Breast

Tuesday, March 10, 2009 9:30 AM

Poster Session III # 36, Tuesday Morning