L. M. DeStefano1, L. Coffua2, E. Wilson3, J. Tchou4, L. N. Shulman5, M. Feldman6, A. Brooks7, D. Sataloff7, C. S. Fisher8 1Mercy Catholic Medical Center,Department Of Surgery,Darby, PA, USA 2Philadelphia College Of Osteopathic Medicine,Philadelphia, PA, USA 3Perelman School Of Medicine,Philadelphia, PA, USA 4Hospital Of The University Of Pennsylvania,Department Of Surgery, Division Of Endocrine And Oncologic Surgery,Philadelphia, PA, USA 5Hospital Of The University Of Pennsylvania,Department Of Medicine, Division Of Hematology And Oncology,Philadelphia, PA, USA 6Hospital Of The University Of Pennsylvania,Department Of Pathology And Laboratory Medicine, Division Of Surgical Pathology,Philadelphia, PA, USA 7Pennsylvania Hospital,Department Of Surgery, Division Of Endocrine And Oncologic Surgery,Philadelphia, PA, USA 8Indiana University School Of Medicine,Department of Surgery, Division Of Endocrine And Oncologic Surgery,Indianapolis, IN, USA
Introduction:
For women with invasive breast cancer (IBC), the incidence of a close or positive margin after partial mastectomy (PM) ranges widely in the literature from 20-70%. The additional surgery required for margins leads to a delay in adjuvant treatment and an increased emotional, financial and cosmetic burden for the patient. Criteria for re-excision are traditionally based on the proximity of the margin. We hypothesize that based on a more comprehensive review of the initial pathology, there are additional factors that can better predict the likelihood of finding residual disease.
Methods:
After IRB approval, we retrospectively identified patients diagnosed with Stage I-III IBC who underwent PM and re-excision at our institution from July 2010 – June 2015. We excluded patients if they had undergone neoadjuvant chemotherapy, had multicentric disease, concurrent contralateral cancer, if current cancer was a recurrence, or if the initial surgery was an excisional biopsy. Bivariate analyses were conducted using two-sample t-tests for continuous variables and Fisher’s Exact tests for categorical variables. A multivariate logistic regression was then performed on significant bivariate analyses variables. A statistical significance was accepted for p <0.05.
Results:
We identified 425 patients who underwent PM and re-excision. Of these patients, 241 (56.7%) were excluded. The remaining 184 patients were included in our analysis and divided into two groups; those with residual disease on re-excision (87 or 47.3%) and those without residual disease (97 or 52.7%). Patients with residual disease were more likely to have higher T and N stages (p=0.02 and p=0.03, respectively), have undergone PM with shave margins (p=0.002) and have only DCIS at their margins (p = 0.02). Of the patients who had residual disease, pure DCIS was found in 14 (16%), invasive disease in 4 (4.6%), and both DCIS and invasive disease in the remaining 69 (79%) patients. The number of positive margins at initial surgery varied significantly between the two groups, with fewer positive margins in patients with no residual disease (p<0.001). In a multivariate logistic regression, surgery with or without shave margins) (p=0.004), number of positive margins (p<0.011), and type of disease present at margin (p=0.026) remained predictive of residual disease at re-excision.
Conclusion:
Our study adds to a growing body of literature on the evaluation of margins after PM. Our data can assist in making decisions regarding the absolute need for additional surgery. While the numbers are unable to predict patients without residual disease with necessary accuracy, they can certainly assist in highlighting which patients will likely have residual disease. Future research should focus on the clinical significance of residual burden of disease.