Doctor's Blog

November, 2009

Mammography

Breast cancer is the second leading cause of death among women in the United States. The primary risk factors are age, prior history of breast cancer, and family history of breast cancer. Every woman’s risk of breast cancer increases as she gets older. Women with a family history of breast cancer in a first degree relative, especially if that relative was premenopausal, should begin screening mammograms at an earlier age. Other risk factors include gene mutation (BRCA1, BRCA 2) and total estrogen exposure such as early menarche, late menopause, late first pregnancy, and hormone replacement therapy.

On November 17, 2009, the U.S. Preventive Services Task Force (USPST) published new guidelines for breast cancer screening.

AGE	MAMMOGRAPHY
40-49	No screening
50-74	Every 2 years
>74	No recommendation

There is insufficient evidence to make a recommendation on screening for women older than 75 years. The risks of overdiagnosis include anxiety, unnecessary imaging tests, and biopsies in women without cancer. Radiation may increase the risk of breast cancer, but at significantly higher doses than routine mammography. No studies have been done on the cumulative effect of regular mammography. Although the risk of breast cancer increases with age, the type of breast cancer found in women > 75 years old usually responds to oral hormone therapy. This older age group has a greater mortality from other health conditions.

The USPST has also recommended against routine self breast exams. Clinical breast exam (performed by physician) has a sensitivity of 40-69% where as a self breast exam has a sensitivity of 12-41%. However, this recommendation is based on a meta-analysis that included several studies done in countries where routine mammography is not used or the trials were conducted before current mammography technology was in place. Mammograms are 77-95% sensitive for screening. However, the sensitivity of mammography in young women is relatively low due to dense breast tissue.

The American Cancer Society recommendations last updated 2003 are as follows:

STUDY	AGE	FREQUENCY
Self breast exam	>20	Once monthly
Clinical breast exam	>20-39	Once every 3 years
Clinical breast exam	>40	Once yearly
Mammography	>40	Once yearly

The American College of Obstretrics and Gynecology recommendations last updated 2003 are as follows:

STUDY	AGE	FREQUENCY
Self breast exam	>20	No recommendation
Clinical breast exam	>20	Once yearly
Mammography	40-49	1-2 years
Mammography	>50	Once yearly

Discussions of breast cancer screening should be addressed with your primary care doctor. A decision on screening should be based on individual risk factors.

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