Objective To investigate whether axillary lymph node dissection (ALND) can be exempted for young breast cancers with reference to the inclusion criteria of American College of Surgeons Oncology Group (ACOSOG) Z0011 trial. Methods A retrospective analysis was conducted on 134 cases of young breast cancer patients admitted to the Second Affiliated Hospital of Nanchang University and the Affiliated Hospital of Jiujiang College from February 28, 2013 to February 28, 2018 who met the inclusion criteria of the ACOSOG Z0011 trial. Patients were divided into case group [n=63, with sentinel lymph node biopsy (SLNB)] and control group (n=71, with SLNB and ALND). General clinicopathologic data, including age, tumor TNM stage, pregnancy or breastfeeding status, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), Ki-67, vessel carcinoma embolus, and tumor Nottingham grade, were collected and compared between the two groups. The 5-year disease-free survival (DFS) and 5-year overall survival (OS) of the two groups were analyzed using the Kaplan-Meier method with log-rank tests. A multifactorial Cox proportional hazards regression model was used to analyze the effect of SLNB implementation alone on the DFS and OS in young breast cancer. Results There were no statistically significant differences in age, pregnancy or breastfeeding status, tumor T classification, tumour molecular classification, tumor Nottingham grade and vessel carcinoma embolus between the two groups (P>0.05). The 5-year DFS rate for the 134 young breast cancer patients was 74.6% and the 5-year OS rate was 83.6%. A statistically significant difference was observed in the 5-year DSF rate between case and control groups (66.7% vs. 81.7%, P=0.033), while there was no statistically significant difference in the 5-year OS rate (77.8% vs. 88.7%, P=0.085). The multifactorial Cox proportional hazards regression model analysis showed that performing SLNB alone was an independent risk factor for DFS in young breast cancer patients (HR=2.261, 95%CI 1.097-4.660, P=0.027), but not for OS (HR=1.976, 95%CI 0.789-4.946, P=0.146). Conclusions Young breast cancers exempted from ALND according to the ACOSOG Z0011 trial inclusion criteria had a higher rate of local recurrence, but their OS was not significant affected. Therefore, whether young breast cancers can be exempted from ALND still requires further clinical trial validation.