看你听从哪个指南.这是最新最保守的---USPSTF的:

来源:

http://www.uspreventiveservicestaskforce.org/uspstf/uspsbrca.htm

但是我个人推荐这个---不一刀切,根据病人的家族史和考虑其它风险,具体地推荐: 

Average-Risk Women

• Monthly breast self-examination (BSE) beginning at age 20 is optional. Awareness of breast changes is encouraged.
• Annual clinical breast examination (CBE) beginning at age 25.
• Annual mammography beginning at age 40.

Women with a Family History – i.e., One or More First-Degree Relative (Parent or Sibling)

• Monthly BSE beginning at age 20 is optional. Awareness of breast changes is encouraged.
• CBE every three to six months starting no later than ten years before the earliest diagnosis in the family.
• Annual mammography starting ten years prior to the earliest diagnosis in the family (but not earlier than age 25 and not later than age 40).
• Consider annual MRI. (Consider performing MRI and mammography at alternating six-month intervals. Consult with your physician.)

Women with a Diagnosis of Atypical Hyperplasia or Lobular Carcinoma In Situ

• Monthly BSE beginning at age 20 is optional. Awareness of breast changes is encouraged.
• CBE every three to six months
• Annual mammography beginning at the time of diagnosis.
• Consider annual MRI. (Consider performing MRI and mammography at alternating six-month intervals. Consult with your physician.)

Women with a History of Mantle Radiation

• Monthly BSE beginning at age 20 is optional. Awareness of breast changes is encouraged.
• CBE every three to six months beginning at the time of diagnosis.
• Annual mammography starting eight years after radiation treatment.
• Consider annual MRI.

For more information: National Comprehensive Cancer Network Breast Cancer Guidelines