Introduction

Screening for Breast Cancer

The primary goal of breast cancer screening is to reduce subsequent breast cancer mortality through early detection. Breast cancer screening, however, yields both false-positive and false-negative results. False-positive results can lead to anxiety, additional costs, and morbidity due to unnecessary diagnostic evaluations. After 10 years of annual screening in the United States, it is estimated that 1 in 2 women will have at least one false-positive mammogram result, and 1 in 5 women will have at least one false-positive clinical breast examination result. False-negative mammography examinations occur in approximately 20-40% of women with breast cancer.

The American Cancer Society recommends that:

• Yearly mammograms start at age 40 and continue for as long as a woman is in good health.

• Clinical breast exams (CBE) should be part of a periodic health exam, about every three years for women in their 20s and 30s and every year for women 40 and over.

• Women at increased risk (e.g., family history, genetic tendency, past breast cancer) should talk with their doctors about the benefits and limitations of starting mammography screening earlier, having additional tests (e.g., breast ultrasound or MRI), or having more frequent exams.

Several studies have found that breast self-examination has no positive effect on breast cancer mortality and leads to almost double the rate of biopsies due to false-positive findings. Therefore, most national groups no longer recommend breast self-examination. However, it is still beneficial for women to become familiar with the contours of their own breasts.

If a change occurs, such as development of a lump or swelling, tenderness, skin irritation or dimpling, nipple pain or retraction (turning inward), redness, itching or scaliness of the nipple or breast skin, or a discharge other than breast milk, you should see your health care professional as soon as possible for evaluation. A lump that is painless, hard, and has uneven edges is more likely to be cancer, but some rare cancers are tender, soft, and rounded. For this reason, it is important that any new breast mass, lump or thickening be checked by a health care professional with experience in diagnosis of breast diseases. Most of the time, these breast changes are not cancer.

The Role of Magnetic Resonance Imaging in Breast Cancer Screening

A study published in the March 29, 2007 issue of the New England Journal of Medicine (Vol. 356; No. 13; pp. 1295-1303) reported that Magnetic Resonance Imaging (MRI) evaluation can detect cancer in the contralateral (opposite) breast in women with recently diagnosed breast cancer that is missed by both mammography and clinical examination at the time of the initial breast cancer diagnosis. In this study, 969 women who were recently diagnosed with breast cancer but had no abnormal findings by either mammography or clinical exam in the opposite breast underwent MRI evaluation. Cancer was detected in the opposite breast in 30 of the 969 (3.1%) of women with a high degree of accuracy as confirmed by a cancer-positive breast biopsy.

Up to 10% of women who are diagnosed with cancer in one breast develop cancer in the oppostite breast. If you have been recently diagnosed with breast cancer, ask your doctor if you should also undergo an MRI evaluation of the opposite breast.

The American Cancer Society recently issued new guidelines recommending MRI screening, in addition to mammography, for some women who are considered to be at high risk for developing breast cancer. Currently, the new guidelines apply only to women who:

• Have tested positive for either the BRCA1 or BRCA2 mutation
• Have a first-degree relative (parent, sibling, child) who has tested positive for the BRCA1 or BRCA2 mutation
• Have been determined to have a lifetime risk of breast cancer of 20%-25% or higher based on various risk factors such as family history of breast cancer, among others
• Have undergone radiation therapy to the chest area between the ages of 10 and 30

• Have been diagnosed (or have a first-degree relative who has been diagnosed) with one of the following syndromes:

  • Li-Fraumeni syndrome - a syndrome that predisposes people to developing certain types of cancers including soft-tisue sarcoma, breast cancer, leukemia, osteosarcoma, and melanoma.
  • Cowden syndrome - a rare syndrome characterized by numerous benign, tumor-like growths called hamartomas that increases the risk for developing certain cancers including breast, thyroid, and uterine cancer.
  • Bannayan-Riley-Ruvalcaba syndrome - a rare inherited disorder that predisposes individuals to the development of both benign and cancerous tumors. The most common sites of cancer are the breast and thyroid gland.

Doctors are still not sure whether MRI screening, in addition to mammography, would benefit women who:

• Have already had breast cancer, including ductal carcinoma in situ (DCIS)
• Have lobular carcinoma in situ (LCIS)
• Have atypical lobular hyperplasia (ALH)
• Have atypical ductal hyperplasia (ADH)
• Have a 15%-20% lifetime risk of breast cancer based on various risk factors such as family history of breast cancer, among others