Abstract P3-01-06: Can axillary evaluation be omitted in patients preoperatively diagnosed with ductal carcinoma in situ by core needle biopsy?

Abstract

Abstract Background Patients diagnosed with ductal carcinoma in situ (DCIS) by core needle biopsy (CNB) have a great chance of upgrading invasive cancer on the final pathology. Positive axillary lymph nodes can be found in these patients. The present study sought to identify clinicopathological factors associated with upgrading and axillary lymph nodes metastasis in patients preoperatively diagnosed with DCIS by CNB. Materials and Methods This study identified 604 patients (cT1-3N0M0) with preoperative diagnosis of pure DCIS by CNB who had undergone axillary evaluation from August 2006 to December 2015 at Fudan University Shanghai Cancer Center (FUSCC). Predictors of upgrading and axillary lymph nodes metastasis were analyzed, respectively. Results Of all 604 patients, 513 (84.93%) and 91 (15.07%) patients had undergone sentinel lymph nodes biopsy (SLNB) and axillary lymph nodes dissection (ALND), respectively. Overall, 121 (20.03%) and 193 (31.95%) patients were upgraded to DCIS with microinvasion (DCISM) and IDC on final pathology, respectively. Positive axillary lymph nodes were identified in 41 (6.79%) patients, of which 35 (5.80%) patients had 1-2 positive axillary lymph nodes, 6 (0.99%) patients had 3 or more positive axillary lymph nodes. Among patients with axillary lymph nodes metastasis, 4 (9.76%), 4 (9.76%) and 33 (80.48%) patients were in DCIS, DCISM and IDC group, respectively. Predictors of upgrading included tumor size on ultrasonography (P=0.001), Ki-67 (P=0.046) and molecular subtype (P=0.007) in univariate analysis. In multivariate analysis, patients with larger tumor size on ultrasonography (>2cm) (OR 1.767, P=0.001) were more likely to be upgraded on final pathology. Also, ER+ HER2+ patients were more likely to be upgraded than ER+ HER2- patients (OR 1.659, P=0.047). Factors associated with axillary lymph nodes metastasis included nipple discharge (P<0.001), tumor size on pathology (P=0.037), number of lesions (P=0.039), axillary evaluation methods (P=0.029) and molecular subtype (P=0.049) in univariate analysis. Whereas, only nipple discharge and larger tumor size on pathology (>2cm) reached statistical significance in multivariate analysis (OR 5.959, P<0.001; OR 2.361, P=0.042). In addition, further analysis showed upgrading on final pathology had a significant influence on axillary lymph nodes status (P<0.001). However, this correlation was not shown between patients with DCIS and DCISM in pairwise comparison. Conclusion The data of upgrading and axillary lymph nodes metastasis in patients with an initial diagnosis of DCIS by CNB was comparable in this cohort with published data. Despite of a 51.98% upgrading rate, the rate of axillary lymph nodes metastasis in these patients is low, which supports the omission of axillary evaluation in selected patients. Citation Format: Si J, Yang B, Guo R, Huang N, Quan C, Chen J, Wu J. Can axillary evaluation be omitted in patients preoperatively diagnosed with ductal carcinoma in situ by core needle biopsy? [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-01-06.