Relationship of Mammography Use to Size and Stage of Breast Cancer at Diagnosis in Older Women

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The summary below is from the full report titled "Regular Mammography Use Is Associated with Elimination of Age-Related Disparities in Size and Stage of Breast Cancer at Diagnosis." It is in the 19 November 2002 issue of Annals of Internal Medicine (volume 137, pages 783-790). The authors are WM Randolph, JS Goodwin, JD Mahnken, and JL Freeman.

What is the problem and what is known about it so far?

Breast cancer is often diagnosed after a woman or her doctor feels a lump in the breast. Mammograms are special x-rays of the breast that can find breast cancer before lumps are felt. The goal of mammograms to screen for breast cancer is to find cancer at early stages, when treatment has the best chance of success. Recently, there has been much debate about the benefits of mammograms. The controversy is greatest for mammograms among women 40 to 49 years of age, but there is also debate about the effectiveness of mammograms in women older than 75 years of age. Many of the studies of mammography have not included large numbers of women in this older age group. Older women generally tend to have breast cancer that is larger and at a more advanced stage at the time of diagnosis than do younger women. It is not known whether this is because of the biology of breast cancer in older women or because older women use mammography less than younger women do.

Why did the researchers do this particular study?

To find out if the size and stage of breast cancer at diagnosis are related to mammography use in older women.

Who was studied?

12,038 women who were older than 69 years of age, were enrolled in Medicare, and had a new diagnosis of breast cancer in 1995 through 1996. To be in the study, the women had to live in 1 of 11 areas included in a national registry of cancer called the Surveillance, Epidemiology, and End Results program.

How was the study done?

The researchers collected information on the number of screening mammograms that women had in the 2 years before diagnosis (none, one, or two or more) and the size and stage of the cancer at diagnosis. They then compared the size and stage of cancer in women 69 to 74 years of age with those in women 75 years of age and older who did and did not have mammograms.

What did the researchers find?

Compared with women 69 to 74 years of age, women older than 75 years of age had larger tumors at diagnosis and were less likely to have had screening mammograms in the 2 years before breast cancer diagnosis. However, older women who used mammography regularly (two or more mammograms at least 11 months apart) had cancer that was similar in size and stage to that in younger women.

What were the limitations of the study?

This study does not address whether mammograms improved quality or length of life for older women.

What are the implications of the study?

These results suggest that regular screening mammography in women 75 years of age and older helps to diagnose breast cancer when it is smaller and at an earlier stage. Further research is needed to determine whether this finding translates into better quality or length of life for older women.