When is the best time to have surgery after neoadjuvant chemotherapy for breast cancer? Neoadjuvant therapy began in the 1970s as a form of preoperative induction chemotherapy for inoperable locally advanced breast cancer (LABC) and inflammatory breast cancer (IBC) to reduce tumor size, control local tumor progression, and increase the chance of surgical cure. Based on current evidence-based medicine, the efficacy of neoadjuvant chemotherapy is the same as that of adjuvant chemotherapy, but allows some patients who cannot be breast conserved to have the opportunity to conserve breast and some patients who are inoperable to have the opportunity to have surgery . How soon after neoadjuvant chemotherapy surgery can be performed has always been a keen concern for clinicians and patients. Domestic and international guidelines do not specify the best time for surgery after neoadjuvant chemotherapy. The latest Chinese Anti-Cancer Association guidelines and norms for the diagnosis and treatment of breast cancer (2015 edition) do not give a clear time, but only state in general terms that breast cancer can be selected for breast preservation or total mastectomy after neoadjuvant chemotherapy downstaging, depending on individual circumstances. The timing of surgery after neoadjuvant chemotherapy is not addressed. Thankfully, there are now published findings. A recent cohort study by Professor Sanford RA and others from the University of Texas M. D. Anderson Cancer Center confirmed that breast cancer patients who underwent surgery more than 8 weeks apart after neoadjuvant chemotherapy had worse 5-year OS and 5-year RFS. The study included 1101 patients with stage I-III breast cancer treated with anthracycline- or paclitaxel-based neoadjuvant chemotherapy between June 1995 and April 2007, of whom 335 (30.4%) had surgery less than 4 weeks after neoadjuvant chemotherapy (TTS <4 weeks), 524 (47.6%) had TTS 4-6 weeks, and 242 (47.6%) had TTS >6 weeks. ＞The number of patients with TTS >6 weeks was 242 (22.0%). The mean follow-up of 94 months revealed that patients with TTS <4 weeks were more likely to progress or have larger tumors. 5-year OS for patients with TTS <4 weeks, TTS 4-6 weeks, and TTS >6 weeks were 79%, 87%, and 81%, respectively, with statistically significant differences. The 5-year RFS and 5-year local recurrence-free survival (LRFS) rates did not differ among the three groups. Multivariate analysis showed no difference in OS, RFS and LRFS between patients with TTS 4 to 6 weeks and patients with TTS >6 weeks compared to patients with TTS <4 weeks. Another analysis showed that patients with TTS >8 weeks had worse OS and RFS compared to patients with TTS 0-8 weeks. The results of these large cohort studies suggest that while OS may be worse in patients with TTS >8 weeks, there is no significant difference in OS, LRFS and RFS in breast cancer patients with TTS <4 weeks, TTS 4-6 weeks, and TTS >6 weeks. The results of this study provide some reference for choosing the timing of surgery after neoadjuvant chemotherapy for breast cancer.