Abstract P3-13-14: Clinicopathologic factors related to surgical margin involvement, reoperation, and residual breast cancer in primary operable breast cancer - An analysis of 2050 patients

Abstract

Abstract Background: Positive or involved margins resulted in higher rates of local recurrence in breast cancer patients and often needs further operations. Identification of patients at increased risk for positive surgical margin may enhance clinical pre-operative decision-making. Methods: A retrospective study with 2050 primary operable breast patients were enrolled in our current margin analysis study, and factors associated with positive surgical margin, re-excision, and residual cancer detection in the re-excision specimen were analyzed. Results: Among them, 151 (7.4%) patients were found to have positive surgical margin involvement. The positive surgical margin involved rate was 11.3% (118/1042) in breast conserving surgery (BCS) patients, and 3.3% (33/1008) in mastectomy group (P<0.001). In multivariate analysis, the positive surgical margin involvement in BCS patients was associated with lower body surface area (BSA), larger tumor size (OR=1.377, CI=0.147~0.498), and pathologic multifocal (OR=3.766, CI=0.639~1.973). MRI use was associated with decrease margin involved rate in BCS patients (OR=0.530, CI=-1.102 ~-0.172). Among the 33 margin involved mastectomy patients, only 3(9.1%) received further excision. Among the 118 BCS patients with surgical margin involvement, 83(70.3%) received further re-excision. Patients with younger age, or DCIS (OR=2.165, CI=0.225~ 1.464) histologic subtypes were factors related to re-operation. Combined with MRI for pre-operative evaluation was associated with decreased re-operation (OR=0.302, CI=-2.129 ~ -0.317) Table 1 Univariate and multivariate analysis of margin involvement in breast conserving surgery patients Univariate analysisMultivariate analysis Odds ratio95% CIpOdds ratio95% CIpBSA0.143-3.365∼-0.5600.007 BMI0.919-0.141∼-0.0030.0320.866-0.214∼0.078<0.001Biopsy method(CNB)1.054-0.227∼0.3090.702 Gross tumor size1.2700.073∼0.4070.0041.3770.147∼0.498<0.001Distance to skin0.551-1.090∼-0.1480.013 Pathological multifocal (Yes)3.2850.587∼1.754<0.0013.7660.639∼1.973<0.001MRI (Yes)0.486-1.118∼0.335<0.0010.530-1.102∼-0.1720.007Stage0.854-0.343∼0.0160.087 Among the 83 BCS patients with positive surgical margin and undergone further surgical excision, 44(53%) was found to have residual tumor in the re-excision specimens. Compared with no residual tumor in the second operation group, no difference in tumor size, lymph node status, pathologic multifocal, or MRI use were found. The only difference was that DCIS (71%, 22/31) histologic subtype was associated with higher residual tumor than other (42.3%, 22/52) type of breast cancer (P=0.021). Conclusions: Lower BSA, larger tumor size, pathologic multifocal were associated with increased risk for positive surgical margin involvement. Combined pre-operative evaluation with MRI was associated with decrease surgical margin involvement and re-operation in BCS patients. Patients with DCIS had positive surgical margin involvement was associated with increased risk for re-operation and residual cancer found at re-excision. Citation Format: Lai H-W, Chen S-T, Chen D-R. Clinicopathologic factors related to surgical margin involvement, reoperation, and residual breast cancer in primary operable breast cancer - An analysis of 2050 patients [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-13-14.