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e12631 Background: Residual disease after preoperative chemotherapy is known to be a poor prognostic factor in triple-negative breast cancer (TNBC). Perioperative use of cisplatin (CDDP) is a well-known, standard treatment for most tumors except breast cancer. In this study, we explore the long-lasting anti-tumor activity of CDDP for TNBC patients. Methods: This research was based on consecutive study of seventy-nine previously untreated stage I–III TNBC patients treated with or without CDDP-based preoperative chemotherapy from 2007 to 2018 at the Kyoto University Hospital. We calculated the residual cancer burden (RCB) using the RCB calculator. All patients were sorted according to their RCB class: the pathological complete response (pCR), and RCB class I (minimal), II (moderate) or III (extensive). Distant disease-free survival (DDFS) was analyzed using the Kaplan-Meier method. Using mass spectrometry, we measured platinum concentrations in serum and normal breast tissue removed during surgery from patients treated with any platinum agents. We examined multiplex cytokine assays from serum sequentially, comparing CDDP and non-CDDP groups. Results: Forty-seven cases were treated with CDDP, and thirty-two did not have CDDP. The pCR rate was 53.2% for the CDDP group and 21.9% without CDDP. Patients with pCR and RCB class I were all distant disease-free. There was no significant difference between each RCB class using CDDP. However, patients belonging to RCB classes II and III with CDDP showed a better prognosis than the same RCB classes without CDDP (hazard ratio = 0.12). Platinum concentrations in serum were correlated with the time from the last dose of platinum agents, but platinum was even detected in serum two years after CDDP. No significant difference was found in the platinum concentrations of serum or normal breast tissue in the pCR and non-pCR groups. We also found that there were significant cytokine expression alteration related to T-cell infiltration only in the CDDP group one year after operation. It is suggested that CDDP may even affect the systemic immune alteration one year after operation. Conclusions: Our data shows that CDDP- based chemotherapy improves DDFS in patients with a substantial residual tumor. CDDP seems to sustain anti-tumor activity for a number of years and interaction with the systemic immune alteration.

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.

164 Background: Neoadjuvant chemotherapy (NAC) is a standard therapy for breast cancer. However, the changes in the lymphatic route to the sentinel lymph node (SLN) before and after NAC are unclear. Indocyanine green (ICG) fluorescence method of SLN biopsy (ICG-SLNB) is useful because of its high identification rate of the SLN and ability to visualize lymphatic routes. Using ICG-SLNB, we compared the lymphatic routes to the SLN (sentinel lymphatic routes) before and after NAC and investigated whether chemotherapy affects the sentinel lymphatic routes. Methods: From October 2010 to April 2012 20 patients received NAC. In 13 cases of clinical node-negative cancer, we performed SLNB before NAC. We recorded the sentinel lymphatic routes before NAC and confirmed the routes at surgery after NAC by using the same method. In 7 cases of clinical node-positive cancer, we recorded the localization of SLN and lymphatic routes by using the ICG fluorescence method before NAC. After NAC, we performed SLNB with axillary dissection and recorded the sentinel lymphatic routes by photography and drawing. Results: Regardless of the presence or absence of lymph node metastasis, the SLN and sentinel lymphatic routes could be detected before and after NAC in all cases. All sentinel lymphatic routes reached the same location of the SLN before and after NAC. In 3 cases, the number of sentinel lymphatic routes had increased after NAC, but the location of the SLN was the same before and after NAC. Other cases showed no changes in the sentinel lymphatic routes. In clinical node-positive cases of pathological complete response, there was no metastasis to the SLN, but there were 2 metastases in the lymph nodes after back-up dissection. Conclusions: ICG fluorescence method provided visual confirmation that the sentinel lymphatic routes were not affected by NAC. This result suggests that SLNB after NAC can be used to safely and positively identify the SLN in clinical node-negative patients. Further investigation would be required to safely perform SLNB after NAC in clinical node-positive patients.

465 Background: Recently, several papers have reported the advantage of neoadjuvant chemotherapy for liver limited metastatic colorectal cancer. In these papers, most study groups used criteria for non-resectability due to size and/or number of metastases. Our criteria for resectability of colorectal liver metastases (CLM) depends on the size of remnant liver volume (>30%) and expected function after the removal of all metastases. Then, we assessed the feasibility and potential benefits of chemotherapy administered before surgery to patients with CLM retrospectively. Methods: From January 2007 to April 2010, 67 chemotherapy-naive patients were diagnosed as CLM without extra-hepatic metastases. After chemotherapy, we assessed the resectability with radiological examination.Then, each case was divided in two groups, resected group and unresected group. Overall survival, median disease-free survival and postoperative complications were analyzed. Results: 63 patients received oxaliplatin-based combination regimen and 4 patients other regimen. 30 patients (resected group) received R0 resection and 37 patients (unresected group) were considered as unresectable. No serious postoperative complications were observed. Overall survival was significantly higher in resected group than in unresected group (42.3 month and 29.1 month; P Conclusions: Intensive treatment with neoadjuvant chemotherapy for CLM is well tolerated. Curative surgery improved significantly overall survival in patients with CLM. Neoadjuvant chemotherapy such as mFOLFOX6 may lead to increased resectability but do not increase postoperative complications. For most patients with resectable CLM, neoadjuvant chemotherapy should be considered the standard treatment. No significant financial relationships to disclose.