M. Asaoka1, K. Narui3, A. Yamada3, N. Suganuma4, T. Chishima5, K. Takabe2, T. Ishikawa1 1Tokyo Medical University Hospital,Department Of Breast Cancer,Tokyo, TOKYO, Japan 2Roswell Park Cancer Institute,Buffalo, NY, USA 3Yokohama City University Hospital,Department Of Breast Cancer,Yokohama, KANAGAWA, Japan 4Kanagawa Cancer Center,Department Of Mammary Gland Endocrine Surgery,Yokohama, KANAGAWA, Japan 5Yokohama Rosai Hospital,Department Of Oncology,Yokohama, KANAGAWA, Japan
Introduction:
Recent studies have indicated that patients who achieved a pathological complete response (pCR) by neoadjuvant chemotherapy (NAC) have better long-term outcomes than those who did not. Recently, the pCR rate is approaching to 50% particularly in patients with hormone-receptor negative disease. If the disease is not recurred locally in cases with pCR and pCR could be accurately diagnosed preoperatively, it may be possible to treat some population of patients without surgery after chemotherapy. We analyzed the outcomes of patients who had achieved pCR by NAC with a special attention to local recurrence and risk factors of recurrence.
Methods:
We investigated disease free survival in 395 patients who were identified as having a pCR from 1599 patients with primary operable breast cancer treated by NAC in 4 institutions (pCR rate of 24.7%; 395/1599). As for subtypes in 395 cases, pCR cases were 50 in Luminal type (pCR rate of 7.2%), 98 in Luminal-HER2 type (32.1%), 116 patients in HER2 type (52.5%), and 131 in triple negative (TN) type (34.2%).
Results:
The median follow-up was 41 months. Recurrent diseases including local recurrence or distant metastasis was found in 5.80% (23/395). According to subtypes, these were 2.00% (1/50) in Luminal type, 4.08% (4/98) in Luminal-HER2 type, 10.3% (12/116) in HER2 type, and 4.58% (6/131) in TN type. Local recurrence was found in 1.2% of all cases (5/395). It was prominent that brain metastasis was frequently observed in HER2 type (12/116). Clinical stage before NAC and nodal status after NAC were found as a risk factor of recurrence in the univariate analysis, and only clinical stage remained statistically significant in the multivariate analysis.
Conclusion:
Except HER2 type, recurrence was not frequent in cases obtained pCR, particularly in cases with an early clinical stage. Local recurrence was rarely observed in any subtype. Based on this result, we think that it is possible to omit surgery in patients highly expected pCR. We have already conducted a multicenter feasibility study to treat without surgery. For cases diagnosed as clinical complete response after NAC by contrast-enhanced magnetic resonance imaging, ultrasound-guided core needle biopsy (CNB) is performed before starting the surgery. The concordance of pathological results between CNB and surgical specimen is examined. The enrollment was completed lately.