According to NCCN Breast Cancer Screening Guidelines, for women between ages 20 and 39 years, a clinical breast examination every 1 to 3 years is recommended, with breast awareness encouraged. For women aged 40 years and older, annual clinical breast examination and screening mammography are recommended, with breast awareness encouraged.
Although controversies persist regarding the benefits and risks of mammographic screening in certain age groups, most medical experts reaffirmed current recommendations supporting screening mammography. The recommendation that women begin annual mammographic screening at age 40 years is based on a consensus statement from the American Cancer Society (ACS) and National Cancer Institute in 1997 and is supported by the ACS guidelines for breast cancer screening published in 2003, as well as the results of meta-analyses of randomized clinical trials.
A second consideration is the time interval of screening in women aged 40 to 49 years. Whether breast screening should be performed annually or every other year remains controversial. The NCCN Breast Cancer Screening and Diagnosis Guidelines Panel elected to follow the ACS guidelines of yearly mammography since mammograms can often detect a lesion 2 years before the lesion is discovered by clinical breast examination. To reduce mortality from breast cancer, yearly screening may be more beneficial.