Several years ago, the U.S. Preventive Services Task Force recommended that women do not need annual mammograms after age 40. There have been other recommendations since.
It is true that mammogram screenings will see the maximal effect in terms of "lives saved" in the 50 to 70 age group, in part because the incidence of breast cancer increases with age and also because younger women have denser breasts which limit the sensitivity of mammography. The maximal effect is actually for women ages 60 to 69. However, there still remains a role for screening mammograms in the 40 to 50 age group, although more women will need to be screened to achieve one life saved when compared to the 50 to 70 age group.
Ideally, a physician would discuss screening with his patients aged 40 to 50 and they together would decide whether to order a mammogram. While my bias rests with screening in this age group if the woman has no personal or family history issues that would raise the concern for breast cancer, deferring screening would be reasonable. If there are personal or family history issues, screening is favored for women ages 40 to 50.
The true risk of screening in women ages 40 to 50 is likely related to the risk of "false positive" results which can lead to further imaging including MRI, biopsy, and more frequent follow-up. This can certainly add to a woman's anxiety and frustration, as well as increase health care costs, but different women will make different decisions regarding how they feel about this issue. Again, when there are personal risk factors or family history, I would continue to favor screening in this age group.
If a breast self-exam does not cause a woman anxiety, she should conduct them, even if its effectiveness has not been proven. If a woman had difficulty performing a breast self-exam or it causes significant anxiety, a yearly clinical breast exam is very appropriate.