Mammograms, Adjuvant Treatment Help Increase Breast Cancer Survival

D.A. Berry et al.

The New England Journal of Medicine, October 27, 2005

Is this for me? You might want to read this article if you are interested in why breast cancer survival rates have increased since 1975.

Background and importance of the study: Over the last 10 to 15 years, more women have begun to live beyond breast cancer. In 1975, about 48 women (age 30 to 79) out of 100,000 died of breast cancer in the United States. In 1990, the number had increased to 50 out of 100,000. In 2000, the number dropped to 38 out of 100,000—a 24% increase in survival rates from 1990. Other countries had similar increases in breast cancer survival rates.

Experts believe that this increase in breast cancer survival happened for two reasons:

• More cancers were found earlier by mammograms—when the cancer is more treatable.
• Advances in breast cancer adjuvant (given after surgery) treatment, such as tamoxifen, powerful new chemotherapy medicines, and better radiation therapy.

To understand how much mammograms and adjuvant treatment each contributed to the increase in breast cancer survival, the study used computer models to explain how and why the number of women dying from breast cancer had dropped so dramatically from 1990 to 2000.

Study design: The National Cancer Institute asked seven teams of researchers from prominent cancer research centers in the United States and the Netherlands to develop computer models that could explain how the breast cancer survival rate increased 24% from 1990 to 2000.

The research teams built computer models that included information on breast cancer, breast cancer detection, and breast cancer treatment. All seven teams used the same national databases of cancer information to feed information into their computer models. The databases included the Surveillance, Epidemiology, and End Results (SEER) registry. This registry is a huge collection of carefully organized information on how many people in the United States get cancer each year (incidence) and how long they live (survival). The National Cancer Institute manages this registry. The researchers also used other national databases on the use of screening mammography, adjuvant treatment, and treatment benefits. The information was from 1975 to 2000.

The computer models then crunched the numbers and determined how much, if any, mammography and adjuvant treatment contributed to the increase in survival rates.

This is the first time a study has looked at the effects of mammography on survival rates separately from the effects of treatment.

Results: The researchers found that 28% to 65% of the increase in the breast cancer survival rate from 1990 to 2000 was due to mammograms. The rest of the increase was due to new adjuvant-therapy drugs.

The increase attributed to mammograms ranged widely (from 28% to 65%) because there were seven models, and each used a slightly different formula to explain the reduction in breast-cancer deaths.

The researchers also found that the number of women getting mammograms increased dramatically from 1975 to 2000. In 1975, about 75% of women over 40 had never had a mammogram. In 2000, more than 80% of women over 40 had had at least one mammogram.

The number of women receiving adjuvant chemotherapy and tamoxifen also increased. The use of these treatments depended on:

• the year in which the women were diagnosed,
• the age of the women,
• the hormone receptor status of the cancer, and
• the stage of the cancer.

In 1975, almost no women received adjuvant chemotherapy for breast cancer. In 2000, about 80% did. Similarly, almost no women received tamoxifen for breast cancer in 1975. In 2000, about 50% did.

Conclusions: All seven research teams concluded that mammograms and adjuvant treatment contributed to increasing breast cancer survival rates from 1990 to 2000. The increase in survival is due to a combination of mammograms and treatment, not either one alone.

Take-home message: This study confirms that both mammograms AND adjuvant treatments (treatments that you get after surgery) have played an important role in increasing survival rates for women with breast cancer.

Because the study separated the effects of mammography from the effects of treatment, the evidence is very clear that mammograms play a key role in increasing survival.

Leading experts, the National Cancer Institute, the American Cancer Society, and the American College of Radiology recommend annual mammograms for women over age 40.

To make mammography work best for you:

• Get your mammogram done in a reputable facility staffed by trained technicians. Seek out digital mammography if you have dense breasts or are age 50 or younger.
• Take advantage of other diagnostic tools—ultrasound and MRI as needed to further check a possible breast abnormality seen on the mammogram.
• Choose a doctor experienced in breast health to minimize the number of necessary biopsies.

There are two types of mammograms:

• Film mammograms: a highly specialized camera takes two pictures of each breast from two directions. The images are recorded on film.
• Digital mammograms: digital mammography uses the same technique as film mammography, except that the image is recorded directly into a computer. The image can then be enlarged or highlighted. This new technology is more expensive than film mammography and not as widely available. About 8% of breast imaging centers in the United States offer digital mammograms.

Research has shown that a digital mammogram is more accurate in finding breast cancer than a film mammogram for women who are younger than 50, have dense breasts, or who still have their periods (or have had a period within the past year). If you're in one of those categories, talk to your doctor about how you can get a digital mammogram.

To make adjuvant therapy work best for you:

• Talk to your doctor about how aggressive you want to be in lowering your risk of the cancer coming back. There is no treatment plan that is right for everyone. Your preferences, lifestyle, and personal beliefs will all play a role in your treatment plan.
• Seek out the best care in each treatment area possible: surgery, medical oncology (medicine therapy: chemotherapy, hormonal therapy, targeted therapies), and radiation oncology. The best care means the most effective treatment with the least amount of side effects, together with a staff that supports you.
• Make a deal with yourself: you will do the best job you can to love yourself, speak up for yourself, take care of yourself, and take advantage of the best medical care available to you.
• View your ongoing therapy as an important insurance plan for extra protection beyond your initial treatment to keep you healthy well into your future. The treatment plan that you and your doctors put together for you is designed to strengthen your outlook for a healthy future. By following it fully, you'll have the best chances of living a long, disease-free life.
• Remember that your treatment plan is not set in stone. You and your doctor will regularly evaluate how the treatment is working. You can always change treatments if another treatment has greater benefits and fewer side effects.