Indication of sentinel lymph node biopsy with breast-conserving surgery for ductal carcinoma in situ considering lymphatic flow

192 Background: Ductal carcinoma in situ (DCIS) has been regarded as curable with resection, but axillary lymph node metastases have been reported in 2% of DCIS patients. Even when DCIS has been diagnosed by preoperative core needle biopsy (CNB), 8% to 38% of the patients have been found to have invasive ductal carcinoma (IDC) on the basis of pathological diagnosis after surgical treatment. The indication of sentinel lymph node biopsy (SLNB) and breast-conserving surgery (BCS) for DCIS is still controversial. Methods: SLNB is a standard surgical technique for early breast cancer treatment, and indocyanine green (ICG) fluorescence method is remarkable in terms of the visualization of lymphatic flow. We analyzed the variation in lymphatic drainage routes from the nipple to the SLN (sentinel lymphatic routes) by using the ICG florescence method in early breast cancer patients and investigated the effects on the localization of the tumor to the sentinel lymphatic routes after BCS. Results: From November 2010 to April 2012, we recorded the sentinel lymphatic routes in 118 patients. All the routes passed through the upper outer quadrant (UOQ) area, and there were more than 2 routes in 53 cases. Of these routes, 73% passed through only the UOQ area and 27% passed through the UOQ via the upper inner, lower inner, and/or lower outer quadrant area. Conclusions: We should confirm the sentinel lymphatic routes by using the ICG florescence method before BCS for preoperatively diagnosed DCIS. If the lymphatic routes do not pass over the extent of resection of BCS, we can omit SLNB in the first surgical treatment and await the final pathological result. However, we should perform SLNB in addition to BCS in cases in which the lymphatic routes pass over the tumor in the region except the UOQ area.