The goal of this observational study is to investigate the features in Chinese male breast cancer (MBC) patients. The main question it aims to answer is:

• The characteristics, treatment patterns and prognosis of Chinese MBC patients. The clinicopathological characteristics, treatment information and follow-up data of participants will be extracted from a Chinese national database (Chinese Society of Clinical Oncology Breast Cancer database) and other involved Chinese centers.

Researchers will investigate the features, survival associated factors and other relevant factors of this population.

The goal of this observational study is to investigate the features in Chinese male breast cancer (MBC) patients. The main question it aims to answer is:

• The characteristics, treatment patterns and prognosis of Chinese MBC patients. The clinicopathological characteristics, treatment information and follow-up data of participants will be extracted from a Chinese national database (Chinese Society of Clinical Oncology Breast Cancer database) and other involved Chinese centers.

Researchers will investigate the features, survival associated factors and other relevant factors of this population.

The collected variables included: survival time, survival status, year of diagnosis, age, stage, molecular subtype statuses, histology, grade, and surgery, radiotherapy and systemic therapies utilization.

Inclusion Criteria:

• Biological sex is male;
• Microscopically diagnosed as primary breast cancer.

Exclusion Criteria:

• Presence of skin-origin malignancy on the breast.

All eligible cases were collected from a Chinese national database (Chinese Society of Clinical Oncology Breast Cancer database) and other involved centers.

A part of Chinese data that support the findings of this study are available from Chinese Society of Clinical Oncology Breast Cancer Database but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Chinese data are however available from the corresponding author upon reasonable request and with permission of Chinese Society of Clinical Oncology Breast Cancer Database.