Mammography Risks Part 3

The debate over whether having mammograms done yearly increases the risk of developing breast cancer prompted the writing of this series of articles. You may want to review Part 1 and Part 2.

In this article *Dr. Boyce presents more information about the risks of developing breast cancer and comes to his conclusions at the end.

 From Dr. Boyce’s article:

“Common conditions or life style factors that increase a woman’s risk of breast cancer by about 40%:

• Never being pregnant or not having children (nulliparity)
• A very early age at first menstrual period (under age 11 years at menarche)
• A very late age at menopause.

Even higher risks are associated with:

• Family history of breast cancer, namely, having several first degree relatives with breast cancer,
• Possessing a damaged or mutated “breast cancer” gene such as BRCA1
• A prior history of breast cancer (developing a second breast cancer is related in part to the same factors associated with developing the initial cancer).

Is it true that while ionizing radiation can definitely cause breast cancer, it is not a major source of breast cancer cases?

Yes. It has been estimated that less than one percent of all breast cancer cases might be attributed to ionizing radiation. Since most of this radiation comes from natural sources, which we have little control over, and from medical sources, which are for our benefit, there are few opportunities to reduce exposure and thus reduce risk.

It should be noted though, that a few groups of women are at high risk of radiation-induced breast cancer for whom surveillance for early detection should be considered.

What groups of women are at especially high risk of developing radiation-induced breast cancer?

• Highest risk: children who received radiation treatments for malignant and nonmalignant conditions.
• Up to 50% of young girls treated for Hodgkin’s disease in the past with very high radiation doses may develop breast cancer in later life.
• Infants treated for enlarged thymus glands.
• Children treated for various forms of cancer.
• Women irradiated for benign breast conditions, including breast inflammation after giving birth.

Most of these types of radiation treatments for non-malignant conditions are no longer given. During treatments for cancer medical oncologists continue to strive to reduce radiation exposures to all healthy tissue, including the breast.

What should a woman do if she received radiation treatments to the chest as a young woman?

Women exposed to high levels of radiation in the past (e.g., radiotherapy to the chest for non-malignant or malignant conditions), should make sure they bring this information to the attention of their health care provider. Together they can then decide upon a medical strategy that might include periodic breast examinations, including mammography or other appropriate breast imaging procedures, to detect any problems early so that treatment might be more effective.”

In the fourth part of this series on mammography we will come to the main stream conclusions about the risks of mammography in regard to the development of breast cancer. From there we will start looking at some alternatives to mammography.

So stay tuned,

Dr. Jo

* John D Boyce, Jr, DSC, Scientific Director,
International Epidemiology Institute, Rockville, MD 20850

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