The 2012 Global Oncology Epidemiology Statistics (Globocan 2012) show that there are 1.677 million new cases of breast cancer worldwide each year, the second highest after lung cancer, and the fifth highest number of deaths at about 522,000. Breast cancer has become the number one threat to women’s health worldwide. The incidence and mortality rates of breast cancer in China are at the lower middle level globally, accounting for 11.20% and 9.20% of the global incidence and mortality cases, respectively. According to the 2015 China Oncology Statistics Report, there are 270,000 new cases of breast cancer each year in China, with the incidence rate in urban areas being two times that in rural areas; and about 60,000 deaths each year, with urban areas being higher than rural areas. Breast cancer accounts for 17.28% of the incidence of malignant tumors in women in China, ranking first, because of the relatively good prognosis, and 7.64% of mortality, ranking sixth. However, in recent years, the incidence and mortality rates of breast cancer in China have been increasing at a high rate, and the trend of cancer incidence in China from 2010 to 2011 shows that the incidence and mortality rates of breast cancer are increasing at the rate of 3.9% and 1.1% per year, respectively. The average age of Chinese patients diagnosed with breast cancer is 45-55 years old, younger than Western women. 2016 National Congress of Clinical Oncology (CSCO) reported: data from Shanghai and Beijing showed that the first peak of breast cancer incidence in Chinese urban women was between 45-55 years old and the second peak occurred between 70-74 years old. A data from Beijing shows that only 5.2% of new breast cancer cases are detected through regular breast cancer screening; 82.1% of women have obvious symptoms by the time they are found to have breast cancer. In the United States, the percentage of breast cancer patients detected through screening is over 60%. Therefore, compared to the U.S. where most patients are diagnosed with carcinoma in situ or stage I, most Chinese breast cancer patients are stage II, and the percentage of stage III and IV is higher than in the U.S. In addition, the rate of stage IV breast cancer is far underestimated in China due to the lack of reporting from medical oncology and radiotherapy departments, as most of the data comes from surgeons. Even more troubling, many patients suffer from delays in treatment that directly affect their prognosis. a 2013 observational study showed that a delay of more than 6 weeks before starting surgical treatment for breast cancer resulted in a five-year survival rate of 80%, while a delay of no more than 2 weeks resulted in a five-year survival rate of 90%. The results of both studies said that more than 40% of patients in China delayed more than 3 months from diagnosis before treatment; delays of more than 1 year even accounted for 11.7% to 17.3% in some less developed regions. As the incidence and mortality rate of breast cancer in China continues to rise, there is an urgent need to increase the proportion of early detection, early diagnosis and early treatment of breast cancer. In particular, public awareness of breast cancer screening and understanding of early diagnosis and treatment need to be further improved. The main factors affecting the incidence of breast cancer in Chinese women are: 1. Reproductive and hormonal factors. Such as long menstrual years (early menarche or delayed menopause), never having given birth, delayed age at first birth, and restricted breastfeeding; 2. Declining fertility (to some extent due to the one-child policy) can also indirectly affect breast cancer risk (e.g., shorter breastfeeding time); 3. Increased incidence due to overweight and obesity. Factors such as low levels of physical activity and traditional healthy eating patterns towards Western diets have led to 25.4% of Chinese women being overweight (body mass index BMI greater than or equal to 25) and 6.7% being obese (BMI greater than or equal to 30). Breast Cancer Screening Guidelines in China Breast cancer screening is a screening tool, which refers to a cancer prevention measure for asymptomatic people, with the aim of early detection, early diagnosis and early treatment of breast cancer, with the ultimate goal of reducing the mortality rate of breast cancer in the population. Medical screening for symptomatic people is called diagnosis. Breast cancer screening is divided into Opportunistic Screening and Massscreening. Opportunistic screening is when a woman goes to a medical institution that provides breast screening on her own initiative or voluntarily; group screening is when a community or unit entity provides breast screening to women of appropriate age in an organized manner. The BRCA1/2 gene is a gene that has been clinically proven to be associated with the development of breast cancer. It is best to determine if a relative who is a carrier of the BRCA1/BRCA2 gene mutation is also carrying the mutation; if they also have the mutation, then the closer they are to the breast cancer patient, the greater the risk of developing the disease. 2.Patients who have had previous moderate or severe atypical hyperplasia of the ducts or lobules of the breast or lobular carcinomainsitu (LCIS). 3. Previously underwent chest radiotherapy. Analysis of breast cancer screening measures There are five main breast cancer screening measures recommended by the CACA Breast Cancer Committee: 1. Mammography: It is recommended that each breast should be routinely photographed in two positions, i.e. cephalopodial (CC) and lateral oblique (MLO) positions; the films should be independently reviewed by two or more professional radiologists. The advantages of mammography are that it is simple and relatively inexpensive to perform, and the most important technical advantage is that it is very effective in showing microcalcifications, and it can also visualize the lymph nodes in the breast, which can detect relatively early cancer, such as ductal carcinoma in situ (DCIS). For example, ductal carcinoma in situ (DCIS) often appears as just a few clusters of small calcifications, and this is where mammography comes into its own. However, mammography does not penetrate well into young dense breast tissue, and the higher the density of the breast, the more difficult it is to detect lesions, so it is generally not recommended for women under 40 years of age who do not have clear risk factors for breast cancer or abnormalities on clinical examination. Routine mammogram has a low dose of radiation and is not harmful to women’s health, but there is radiation after all, so normal women do not need to undergo this examination repeatedly in a short period of time. 2.Breast ultrasound: A non-invasive test that determines whether the human tissue is normal based on the strength of the echoes, and can help infer the benignity or malignancy of the lump based on the blood flow of the tissue and the condition of the nearby lymph nodes. The advantages of ultrasound are its simplicity, affordability, lack of radiation damage, safety, and independence from the type of breast gland, which can make up for the difficulty of detecting dense breast masses with mammography. Ultrasound examination of the breast is mainly used to check for occupational diseases of the breast, especially for young women with fibroadenoma, breast cysts, and breast hyperplasia, which are more clearly identified. However, ultrasound examination also has some limitations, such as it can be affected by equipment and doctor’s experience; it is not sensitive to show microcalcifications (while sometimes such microcalcifications, often, are reliable signs for diagnosing breast cancer) and is not very accurate; it is difficult to diagnose and identify non-lumpy lesions. Because of the high percentage of premenopausal patients and relatively dense breast, ultrasonography can be used as a combined screening measure with mammography or as a supplemental screening measure for those with BI-RADS (Breast Imaging Reporting and Data System of the American College of Radiology) level 0. Supplementary screening measures for those with a grade of 0. Mammography combined with ultrasound is recognized as the best “golden combination” in the industry. [Note: The American College of Radiology’s BI-RADS is the standard for reporting mammograms and is divided into 8 levels, of which level 0 refers to the need for other imaging studies (ultrasound, MRI, local compression photography and magnification). 3.Magnetic resonance imaging (MRI) of breast: it can be used as a supplemental examination measure for suspected cases detected by mammography, breast clinical examination or breast ultrasound; it is used in combination with mammography for breast cancer screening in certain breast cancer high-risk groups. MRI examination has many imaging advantages, one of which is the absence of radiation and its excellent resolution of soft tissues. Since the breast is a soft tissue organ and is very sensitive to radiation, MRI is very advantageous in the diagnosis of breast disease and can be an important complementary method to X-rays and ultrasound. The limitations of MRI are that it is more time-consuming and more expensive than X-ray and ultrasound; some patients (with metal implants or claustrophobia in the body) are unable to undergo it. 4.Clinical Breast Examination (CBE): A physical examination of bilateral breast and its surrounding lymphatic tissues conducted by a professional physician. The effectiveness of clinical breast examination alone as a method of breast cancer screening is not certain, and there is no evidence that this method can improve the early diagnosis rate of breast cancer and reduce the mortality rate. Therefore, it is generally recommended as a combined screening measure for breast cancer screening, which may compensate for the omission of mammography screening. 5. Breast self-examination (BSE): It is recommended for premenopausal women to choose 7 to 14 days after menstruation to self-examine bilateral breasts and lymph nodes in upper, lower, anterior, posterior and median areas of the armpits by observation, touch and pressure in three steps. Breast self-examination cannot improve the early diagnosis rate of breast cancer and reduce the mortality rate. However, because it can increase women’s awareness of cancer prevention, primary health care workers are still encouraged to teach women about once-a-month breast self-examination. Comparison of Screening Guidelines by Institution On January 12, 2016, the Annals of Internal Medicine (AnnInternMed) published online the final version of breast cancer screening guidelines issued by The UnitedStatesPreventiveServicesTaskForce (USPSTF). The final version of the screening guidelines still does not recommend routine mammography for women aged 40-49 years, and it is best to follow your doctor’s advice about when and how often to start routine mammography. According to USPSTF, this recommendation is a level C recommendation, which means that individualized decisions should be made based on individual preferences, weighing the pros and cons. In recent years, with improved treatment outcomes for advanced breast cancer and concerns about overdiagnosis, organizations other than the USPSTF have re-evaluated breast cancer screening tools such as mammograms, clinical breast exams and breast self-exams based on research data and updated their published breast cancer screening guidelines. 2015, the World Health Organization’s International Agency for Research on Cancer (WHO In 2015, the International Agency for Research on Cancer (WHO/IARC) and the American Cancer Society (ACS) updated their breast cancer screening guidelines in June and October, respectively, and their updated recommendations were closer to those of the USPSTF. For example, the new ACS guidelines recommend that the age for women to have one mammogram per year be changed from 40 years to 45-54 years. How exactly should I choose breast cancer screening? Chinese women should keep the following in mind: 1. Age <40 years: clinical breast examination + breast ultrasound is preferred, if there is a suspicious lesion, mammogram can be added; 2. Age ≥40 years: clinical breast examination + mammogram + breast ultrasound (dense breast plus ultrasound) is preferred; 3. If you are at high risk of breast cancer, you should start to have annual mammogram after 20 years old. If necessary, breast MRI can also be added, you can consult your doctor for details.