To evaluate the rate of axillary lymph nodes metastasis in ductal carcinoma in situ with microinvasion (DCIS-MI).

The Cochrane Library, Web of Science, CNKI, Wanfang Database, VIP and China Biomedical Literature Database were searched for relevant literatures about DCIS-MI who underwent sentinel lymph node biopsy (SLNB) or axillary lymph node dissection (ALND) and reported the rate of nodes metastatic. Meta analysis was performed using Stata 16.0 software.

A total of 43 studies involving 17 502 patients met the eligibility criteria. The rate of axillary lymph nodes metastasis in DCIS-MI was 7% (95% CI: 6%-8%). Subgroup analysis showed that, DCIS-MI axillary lymph node metastasis rates were 6% and 11.1% in retrospective study and prospective study by study type respectively; DCIS-MI axillary lymph node metastasis rates were 10.1% and 12.1% in staining with ⁹⁹Tc^m Sulfur Colloid and staining with blue dyestuff combined with ⁹⁹Tc^m Sulfur Colloid by using SLNB staining method respectively; DCIS-MI axillary lymph node metastasis rates were 4.8%, 8.6%, and 9.6% by confirming sentinel lymph node positive method respectively; DCIS-MI axillary lymph node metastasis rates by region 5%, 12%, and 6% in Asia, Europe, and the America. In addition, there were significant differences between two groups based on study type, SLNB staining method, lymph node positive confirmed method, and area (P<0.05).

The rate of axillary lymph nodes in DCIS-MI was 7%, and patients had good prognosis. However, the recurrence and metastasis rates of DCIS-MI had been shown to be higher in node negative groups who also received lower rates of systemic therapy compared to the node positive patients groups. Therefore, it is reasonable for DCIS-MI patients to perform axillary lymph node staging, which can provide the evidence for systemic treatment. ALND should not be performed routinely, but SLNB is necessary.