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Abstract P6-14-08: Impact of immediate breast reconstruction after mastectomy on the short and long-term outcome of patients receiving neoadjuvant chemotherapy

Background and Purpose In breast cancer patients receiving neoadjuvant chemotherapy (NAC), immediate breast reconstruction (IBR) is controversial. We retrospectively investigated whether IBR after mastectomy influenced the short and long-term outcome of patients receiving NAC. Patients and Methods Between April 2007 and December 2017, 525 breast cancer patients received NAC at our hospital of which 186 patients underwent total mastectomy alone, 55 underwent total mastectomy followed by IBR, and 284 underwent breast conserving surgery (BCS). Patients receiving IBR were compared to patients who did not receive IBR. The NAC regimen was 4 cycles of epirubicin, 5-fluorouracil and cyclophosphamide followed by 4 cycles of docetaxel. Decision making for post mastectomy radiotherapy (PMRT) followed national comprehensive cancer network guidelines. PMRT is not contraindication for patients receiving IBR, however risk such as capsular contracture was informed to patients. Tissue expander was replaced to silicon breast implant within two to three months, and radiotherapy started within 4 to 6 weeks after surgery. In other surgical-procedure, such as direct-to-implant breast reconstruction, BCS or mastectomy alone, radiotherapy started 6-8 weeks later. Post-mastectomy radiation was applied equally with the same selection criteria to both groups. Results Patients in the IBR and BCS groups were on average younger than patients in the mastectomy alone group (p After a median of 76.4 month, 2 patients (4.2%) in the IBR group, 13 patients (4.5%) in the BCS group and 17 patients (9.1%) showed locoregional recurrences. Five-year locoregional recurrence-free survival was 96.1% in the IBR group, 96.8% in the BCS group and 90.1% in the mastectomy alone group (p= 0.032). Five-year distant disease-free survival was 92.9 % in the IBR group, 93.9% in the BCS group and 85.3 % in the mastectomy alone group (p= 0.0008). Five-year overall survival was 98.0 % in the IBR group, 98.4% in the BCS group and 92.3 % in the mastectomy alone group (p= 0.0004). Multivariate analysis showed that IBR was not associated with worse prognosis. Transverse rectus abdominis muscle flap necrosis was seen in one patient. Any breast implant or tissue expander related complications including infection and capsular contracture were not encountered. Conclusions IBR after total mastectomy can be performed safely and was not associated with worse prognosis in patients receiving NAC and therefore IBR may be the preferred strategy in select cases. Citation Format: Hiroko Nogi, Makiko Kamio, Takashi Kazama, Naoko Shimada, Takayuki Ishigaki, Hisashi Shioya, Yasuo Toriumi, Eijiro Nagasaki, Hiroshi Takeyama. Impact of immediate breast reconstruction after mastectomy on the short and long-term outcome of patients receiving neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-14-08.