Dr. David Euhus of the Johns Hopkins Breast Center answers questions on when to begin scheduling a mammogram, what to do if you recognize a breast cyst and more.

I know several people in their 30s with breast cancer. Why are we told not to get mammograms until we are 40?

The incidence of breast cancer is strongly related to age. As we get older, our risk increases. While women get breast cancer in their 30s, screening the entire population in their 30s likely would not provide the intended benefit of early diagnosis.

Is there any risk in having breast mammograms? If so, why do we encourage women to have such a risky screening test?

To our knowledge, for those over the age of 30, there is no evidence that the radiation exposure of a mammogram increases breast cancer risk.

Are cysts in the breast dangerous? Can they become cancerous and should they be removed?

There are many different types of cysts. Most are called simple cysts and are not related to breast cancer or the risk of breast cancer. The best way to evaluate cysts is with an ultrasound of the breast.

Should all women get an ultrasound and a screening mammogram yearly?

The screening guidelines that we follow recommend annual mammograms beginning at age 40. This may be different for high-risk women. The use of ultrasound as a supplement to a screening mammogram depends on several factors.