Can We Skip Sentinel Lymph Node Biopsy in Patients Who Have Microinvasive Breast Cancer?

Abstract

Abstract Background: Sentinel lymph node(SLN) biopsy in patients with ductal carcinoma in situ(DCIS) was controversial. We may skip SLN biopsy when we performed conserving operation with small sized DCIS. But sometimes we can find DCIS with micro-invasive breast cancer (MIC) after operation. Should another operation be performed? We determined the incidence of positive axillary lymph node (ALNs) in patients with MIC, and the predictive factors of ALNs metastasis in these patients. Methods: Between July 1989 and January 2008, 9046 patients had operations performed on invasive breast cancers at Asan Medical Center. From July1989 to February 2003, ALND was performed to surgically stage the axilla. Since May 2003, SNB has been routinely performed for all cases. Patients who were treated with neoadjuvant chemotherapy and those who had no identifiable ALNs at surgery were excluded from the study. We retrospectively checked clinical and pathologic variables including diagnosis, patient demographics, size of DCIS, grade, multi-focal lesion, hormone receptor status, lymphatic invasion status etc. Results: 265 patients were identified with microinvasive (pathologic stage T1mic) breast cancer. Among these patients, 12 patients didn't have ALN study. 2 patients had bilateral MIC. The research was conducted on the remaining 255 cases. There were 13 cases of ALN metastases identified in this group of patients(5%). Young age (p=0.006), multifocal lesion (p=0.040) and lymphatic invasion (p<0.0001) were predictive factors for ALN metastases. There was no incidence of metastatic ALNs among the old age (≥50) patients of this group. Conclusion: As the incidence of ALN metastases in MIC patients is very small, particularly in those who had no lymphatic invasion, single lesion and among old age patients. So we think conservative treatment is one of the available options for these patients. However, due to the size of the subject group in this study, it needs to be validated through extensive prospective research. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1019.