Abstract Background: Endoscopy-assisted breast surgery (EABS) performed through minimal axillary and/or periareolar incisions is a possible alternative to conventional surgery for certain patients with breast cancer. In this study, we report the early results of an EABS program in Taiwan. Methods: The medical records of patients who underwent EABS for breast cancer during the period May 2009 to December 2014 were collected from the Taiwan Endoscopic Breast Surgery Cooperative Group database. The Taiwan Endoscopic Breast Surgery Cooperative Group (T-EBSCG) was established to monitor the effectiveness of and clinical outcome associated with EABS in Taiwan. The T-EBSCG comprises members from three major endoscopic breast surgery centers, namely Changhua Christian Hospital, National Cheng-Kung University Hospital,and Taipei Medical University Hospital in Taiwan. Data on clinicopathologic characteristics, type of surgery, method of breast reconstruction, complications and recurrence were analyzed to determine the effectiveness and oncologic safety of EABS in Taiwan. Results: A total of 315 EABS procedures were performed in 292 patients with breast cancer, including 23 (7.8%) patients with bilateral disease. The mean tumor size of these 315 EABS was 2.2 ± 1.8 cm, and 44(13.9%) of them were multifocal/multicentric breast cancer. Lymph node metastasis was found during 23.3% of the procedures. The stage distribution of them were stage II cancer (n=103, 34.4%), followed by stage I cancer (n=92, 30.7%), ductal carcinoma in situ (stage 0) (n=86, 28.7%), and stage III breast cancer (n=19, 6.3%). The number of breast cancer patients who underwent EABS increased initially from 2009 to 2012 and then stabilized during the period 2012-2014. The most commonly performed EABS was endoscopy-assisted total mastectomy (EATM) (85.4%) followed by endoscopy-assisted partial mastectomy (EAPM) (14.6%). Of the 269 patients who underwent EATM, 198 (73.6%) received immediate breast reconstruction. The majority (72.2%) of them received implant-based (cohesive Gel implant or tissue expander) reconstruction and the remaining 27.8% received autologous pedicled TRAM flap for breast reconstruction. Endoscopic assisted nipple sparing mastectomy with Gel implant reconstruction was the most frequently performed EABS now. During the six-year study period, there was an increasing trend toward more frequently use of EABS in the management of breast cancer when total mastectomy was indicated (EATM) than breast conserving surgery (EPM). Overall, the rate of complications associated with EABS was 15.2% and all were minor and wound-related. There were no major or life threatening complications. The positive surgical margin rate was 1.9%. During a median follow-up of 26.8 months (range, 3.3-68.6 months), there were 3 (1%) cases of local recurrence (1 ipsilateral breast recurrence, 1 axillary local recurrence, and 1 core needle biopsy tract recurrences), 1 (0.3%) case of distant metastasis, and 1 death. Conclusion: The EABS program in Taiwan showed that EABS is a safe procedure and results in acceptable cosmetic outcome, these findings could help to promote this under-used surgical technique in the field of breast cancer. Citation Format: Lai H-W, Kuo Y-L, Hung C-S, Chen S-T, Chen D-R. Current trend and indications of endoscopy-assisted breast surgery for breast cancer: Experience from Taiwan endoscopic breast surgery cooperative group. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-12-16.