BACKGROUND Breast cancer is the most common malignancy in women all around the world. According to the latest statistics in 2018, there were more than 2.08 million new breast cancer cases all around the world and more than 620000 deaths; the proportion of breast cancer deaths in women with cancer is 15%. By studying age, clinicopathological characteristics and molecular classification, age at menarche, age at birth, number of births, number of miscarriages, lactation time, surgical history of benign breast lesions, history of gynecological diseases, and other factors, we retrospectively summarized and compared the disease history of patients with primary breast cancer and patients with benign thyroid tumors admitted to our hospital in the past 10 years to explore the clinicopathological characteristics and risk factors for primary breast cancer. AIM To investigate the clinical and pathological features and risk factors for primary breast cancer treated at our center in order to provide a reference for the prevention and treatment of breast cancer in the Zhuhai-Macao region. METHODS Through a retrospective case-control study, 149 patients with primary breast cancer diagnosed and treated at Zhuhai Hospital of Guangdong Provincial Hospital of Traditional Chinese Medicine from January 2013 to March 2020 were included as a case group, and 165 patients with benign breast tumors diagnosed and treated from January 2019 to March 2020 were included as a control group. The data collected included age, age at menarche, age at first birth, number of births, number of miscarriages, lactation time, history of surgery for benign breast lesions, history of familial malignant tumors, history of gynecological diseases, history of thyroid diseases, and the tumor characteristics of the patients in the case group including pathological diagnosis, pathological type, tumor size, lymph node metastasis, distant metastasis, stage, and molecular classification, among others. In the case group, the chi-square test was used to analyze the clinical and pathological features of patients in three age groups (< 40, 40-59, and <greater than or equal to> 60 years). A multifactor logistic regression analysis was used to analyze correlations between the two groups. RESULTS Among 149 patients with primary breast cancer, the average age was 48.20 12.06 years, and the proportion of patients at 40-59 years old was the highest, accounting for 61.8% of cases. The molecular type was mainly luminal B type, accounting for 69.2% of cases, and at the time of diagnosis, the tumor stage was mainly stage I/II, accounting for 62.4% of cases. There were no statistically significant differences in the distributions of tumor location, pathological type, tumor size, lymph node metastasis, stage, or molecular classification among the three age groups (< 40, 40-59, and <greater than or equal to> 60 years) (P >= 0.05). The differences in the distribution of distant metastasis among the three age groups (< 40, 40-59, and <greater than or equal to> 60 years) were statistically significant (P < 0.01). The differences in lactation time, history of familial malignant tumors, history of gynecological diseases, and history of thyroid diseases between the two groups were not statistically significant (P <greater than or equal to> 0.05). The differences in age at disease diagnosis, age at menarche, and history of surgery for benign breast lesions were statistically significant (P < 0.01). The difference in age at first birth was also statistically significant (P < 0.05). CONCLUSION The highest incidence of breast cancer in the Zhuhai-Macao region is present among women aged 40-59 years. There is a larger proportion of stage I/II patients, and the luminal B type is the most common molecular subtype. Distant metastasis occurs mainly in the >= 60-year-old group at the first diagnosis; increased age, late age at menarche, and late age at first birth may be risk factors for primary breast cancer, and a history of surgery for benign breast lesions may be a protective factor for primary breast cancer.