Prevention, Screening and Health Maintenance

Family Medicine Clerkship
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Breast Cancer   -   Evidence & Cases

Screening Mammography

How does mammogram differ with age?

In young women the breast is often extremely dense.  Glandular tissue and cancer are dense (white) in a mammogram. Hence it is difficult to distinguish cancer from normal dense glandular tissue in young women.  

As women age, there is fatty infiltration of the breast associated with atrophy of glandular tissue. Fat is lucent (dark) in mammogram. 

At what age should you start the screening mammography for detection of breast cancer? How frequently it should be done?   

Various recommendations are made by different organizations. The generally accepted recommendation is a mammogram each year starting at age 40. This is recommended by the American Cancer Society and the American College of Radiology in addition to many other organizations.

What is the incidence of breast cancer corrected for age?
After which age does the risk of developing breast cancer steadily increase in women?

After the age of 40, a woman's risk of developing breast cancer steadily increases.

Who is at high risk for cancer breast? What risk factors are associated with an increased chance of developing breast cancer?

 Risk factors for breast cancer include:

Estimate the accuracy (sensitivity and specificity) of mammography as a screening test.

The sensitivity and specificity values are for women aged 50-70:

What is the false positive rate of mammography? 

Given a specificity of 83-98%, false positives occur 2-17% of the time.   

What conditions give rise to false positive suspicion for cancer breast?

Several benign breast conditions can produce a spiculated density, which may be indistinguishable on mammography from carcinoma.

Spiculated mass density has been encountered in:

Also, it may be difficult to distinguish benign from malignant calcifications.

Case 1

A 25 y/o woman who has a strong family history of breast cancer comes to your office inquiring about screening mammography at her age. What would you tell her? 

A. Screening mammograms should be done once a year.
B. Screening mammograms should be done once every two years.
C. Screening mammograms are not recommended at this age.

Answer C  

Let us now evaluate the evidence and controversy with regards to screening mammography.

What are some potential disadvantages for screening mammography?
What potential harms can occur from screening for breast cancer with mammography?
Is there a potential risk for radiation-induced breast cancer in women who receive annual mammograms?
What factors contribute to the annual cost of performing screening mammograms for women as indicated?
Screening mammography certainly detects early cancer.  What evidence do we have to show that screening mammography and early detection of cancer prolongs life? What is the survival advantage of early detection of breast cancer?
Screening mammogram reveals a suspicious lesion for cancer in left breast. No mass is palpable. How would you proceed?
Case 2

A 35 year woman with a strong family history of breast cancer comes to the clinic inquiring about screening. She has no other risk factors other than family history. What would you tell this patient regarding the current recommendations for breast cancer screening?


Discussion of current recommendations:

What are the current recommendations?
Case 3
CHIEF COMPLAINT: I want a mammogram.

A 40 year old female presents to clinic asking for a mammogram. She is a healthy, active woman with a medical history significant only for hypothyroidism and cholecystectomy at age 35. She is a homemaker and mother of 2 children. She has never smoked cigarettes, and drinks one glass of wine with dinner each night. She states that her mother died of breast cancer at age 60, and a previous family doctor had advised her to start screening for breast cancer with mammograms at age 40. The patient's obstetric/gynecologic history includes the following information: menarche age 12, menses occurs regularly every 28 days and lasts for 5 days. She is gravida 2, para 2.

PHYSICAL EXAM: The breasts are examined with the patient in sitting and supine positions. The breasts are large, round and symmetrical. The contour of each is smooth with no evidence of dimpling, retraction or edema. The nipples and areola are symmetrical, pink-tan and show no eczema or inversion. Palpation of both breasts and axilla reveals no abnormalities.

Answer: This patient should have a screening mammogram