[132] The Effects of Additional Tumor Cavity Sampling at the Time of Breast Conserving Surgery on Final Margin Status, Volume of Resection, and Pathologist Work-Load

KL Chandler, J Park, M Rizzo, G Birdsong, MB Mosunjac. Emory University, Atlanta, GA

Background: The effect of removing additional tumor cavity margins at the time of initial breast conserving surgery (BCS) have not been demonstrated. A few studies suggest that there is a reduction in the re-operation rate for microscopic presence of tumor at the margin. This study compares margin status, volume of breast tissue excised, and pathologist work-load in two groups of patients who underwent BCS with or without resection of 4 or 5 additional margins (BCS+M).
Design: We retrospectively analyzed 320 patients who underwent BCS or BCS+M for ductal carcinoma in situ (DCIS) or infiltrating ductal carcinoma (IDC) from 2004 to 2007. Based on the distance from the tumor to margin of resection we classified the margins as negative (1 mm), close (< 1 mm) or positive (tumor cells at inked margin). Volume of breast tissue excised was calculated in cm³ from the tri-dimensional size recording in the pathology report. Also, the number of submitted blocks per case was extracted from the pathology report. Data were statistically analyzed using Fisher's Exact and Wilcoxon rank sum test.
Results: Of 320 cases analyzed, 199 (62.2%) underwent BCS and 121 (37.8%) had BCS+M. Overall, patients with BCS+M had a higher negative margins rate (89.3%vs 75.4% p<0.05). Also, there was no overall difference in total volume of breast tissue excised. However, when DCIS and IDC were analyzed separately, only patients with IDC showed a higher negative margin rate (p< 0.001) and a lower volume of breast tissue excised (p =0.03). For DCIS, there was no difference in margin status and volume of breast tissue removed with either type of surgery. Also, there was no significant difference in number of submitted blocks for cases with positive/close margins.
Conclusions: This study suggests that resection of 4-5 additional margins during BCS for early stage invasive breast cancer significantly reduces rate of positive margins while there is no advantage in such surgical approach for DCIS. Interestingly, for BCS + M, this study suggests that the volume of tissue resected for cases of IDC was actually statistically significantly decreased; however, there was no overall significant difference in the volume of tissue resected both for DCIS and IDC. Also, comparison of the number of blocks submitted suggests that surgery with additional margin resections does not significantly increase the pathologist work-load or time spent per case.
Category: Breast

Wednesday, March 11, 2009 9:30 AM

Poster Session V # 16, Wednesday Morning