BACKGROUND: This study investigated the differences in clinicopathologic features and surgical treatment between an Italian and a Chinese cohort of premenopausal women with breast cancer, and highlighted the potential advantages of international medical exchange projects. METHODS: Premenopausal women who underwent surgical treatment between 2012 and 2016 at one Italian and one Chinese institution participating in a medical exchange program were compared. Factors associated with the probability to receive mastectomy were determined via logistic analysis. Changes in surgical management at the Chinese institution in the period 2018-2019, after the exchange program, were also evaluated. RESULTS: A total of 505 patients, 318 from Italy and 187 from China, were evaluated. The Chinese patients had more frequently advanced-stage tumours, large tumour size (30.9 vs. 18.1 mm, p < 0.01), invasive carcinoma (92.5 vs. 83.3%, p < 0.01), positive axillary lymph nodes (54.5 vs. 27.4%, p < 0.01), Her-2 positivity (36.4 vs. 22.0%, p < 0.01), and high proliferative index (55.1 vs. 30.2%, p < 0.01). Positive oestrogen receptor status and rates of triple-negative breast cancer did not differ (77.0 vs. 69.5%, p = 0.09 and 14.2 vs. 16%, p = 0.56, respectively). Mastectomy rates were higher among Chinese women (85 vs. 41%, p < 0.001), whereas use of sentinel node biopsy was more frequent among Italian women (77 vs. 33%, p < 0.001). Chinese women had more than 4-fold higher risk of receiving mastectomy. In the last 2 years, the rates of breast-conserving surgery and sentinel node biopsy at the Chinese institution increased from 15 to 23%, and from 33 to 42%, respectively. CONCLUSIONS: Tumour features and surgical strategies for premenopausal breast cancer may differ significantly between Italy and China. Since the international exchange program, patients from the Chinese institution have been offered more frequently less invasive surgery. International exchange programs can help in designing epidemiological studies which may be useful for strategies to improve breast cancer management and control.