Despite the high level of interest and investment in breast cancer screening, the pros and cons of mammography screening and how to select the right population for screening and screening strategies remain a challenge. The last edition of the American Society of Oncology breast cancer screening guidelines was developed in 2003 and has been updated. In the 2003 edition, the ACS recommended annual mammography screening for all women beginning at age 40, regular clinical breast exams for women aged 20-40, and annual CBE for women aged 40 and older. The new guidelines emphasize screening for women at average risk, recommending annual mammography for women aged 45 to 54 and biennial mammography for women aged 55 and older until life expectancy is less than one year. The new guidelines emphasize screening for women at average risk, recommending annual mammography for women aged 45 to 54 years and biennial mammography for women aged 55 years and older until life expectancy is less than 10 years, and do not recommend routine CBE for any women. I. Key points of the new guidelines 1. 2. More frequent annual screenings are recommended for women aged 45 to 54 years. 3. Do not recommend routine CBE, which is very different from the previous guidelines and stronger than the USPSTF language, which only states that there is insufficient evidence to recommend or oppose CBE. 4. Recommend discontinuing screening when life expectancy is less than 10 years, as the USPSTF only states that there is insufficient evidence to support the benefits or harms of screening for women 75 years and older. Clinical recommendations The ACS guidelines and the USPSTF guidelines are the 2 main current guidelines, and the updated ACS guidelines are more consistent with the USPSTF guidelines in that both agree that mammography screening for women under 45 years of age does more harm than good, and that women over 55 years of age should be screened with mammography every 2 years. The difference is that the ACS recommends annual screening for women 45-54 years of age, while the USPSTF does not recommend routine screening for women 45-49 years of age and recommends screening every two years for women 50-54 years of age. The majority of breast cancer patients’ prognosis is not affected by mammography screening. Studies have shown that mammography can reduce death in 15% of breast cancer patients aged 40-60 years, meaning that 85% of breast cancer patients aged 40-60 years will not benefit from mammography screening. For women at average risk, the decision to routinely screen with mammography must take into account the risks of mammography screening, such as the potential for overdiagnosis and associated overtreatment, as well as the risk of false positives and unnecessary biopsies. The decision to perform mammography screening and the frequency of screening should be based on the patient’s risk of developing breast cancer. Despite the large body of literature on mammography screening, the current evidence is not sufficient to help women decide whether to use mammography screening and the strategy for screening. The future of breast cancer screening will require more individualized information about breast cancer risk, which will depend on the availability of risk assessment tools and the application of new technologies such as genomics. Identifying those at high risk of developing breast cancer will allow for more targeted identification of those who need to be screened and selective high-frequency screening, thus limiting the downside of screening to the greatest extent possible.