How Effective are Mammograms and Breast Self-Exams?
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How Effective are Mammograms and Breast Self-Exams?

Two recent studies challenge the long-held beliefs that mammography and breast self-exam are essential tools for monitoring your breast health. Here's what you need to know.


The firestorm of controversy first arose in 2000 when a Canadian study raised questions about life expectancy rates for women who received yearly mammograms versus those who had not. Then came the second surprising report, when the Journal of the National Cancer Institute (October 2, 2002) published the results of a recent study concluding that breast self-exams did not necessarily increase life expectancy, either.

For a woman trying to make decisions about protecting her breast health, deciphering the smoke signals can feel confusing, at best. What should a woman do to protect herself?

The Mammogram Controversy

In September 2000 a Canadian research team released the results of a 13-year study of approximately 40,000 women aged 50 to 59. From 1980 to 1993, researchers followed the progress of two groups of women: those who received only yearly physical exams and those who received annual physicals as well as a yearly mammogram.

Researchers found that while more cancers were detected in the women who'd received mammography, their death rates from the disease were no lower than the rates among women who had physical exams only. (There were 88 deaths out of 622 incidences of breast cancer, or 14 percent in the mammogram group, and 80 deaths out of 612 incidences, or 13 percent, in the physicals-only group). The researchers' conclusion: yearly mammograms did not necessarily lead to an increase in survival rates once cancers were discovered.

The Breast Self-Exam Brouhaha

The breast self-exam (BSE) controversy revolves around an 11-year study of female factory workers in Shanghai, China. The results were published in the October 2, 2002 issue of the Journal of the National Cancer Institute.

Shanghai was chosen as the test area because most of the women in the region were employed at one factory throughout their working life. Since they received all of their medical care through their employer, it was much easier for researchers to chart their progress. Approximately 133,000 women were extensively trained in breast self-exam (BSE), while another 133,000 were only given yearly physical exams. These women were not trained in BSE. BSE and yearly physicals were the only screening options available to these women. They did not receive mammograms.

Researchers determined that, even though the women who received extensive BSE training discovered more benign tumors and underwent more biopsies, their death rates from breast cancer were not significantly lower. They found that BSE alone did not necessarily lead to early detection of breast cancer.

Physicians Respond

American doctors dispute many aspects of the Canadian study, beginning with the methodology used for selecting subjects; it wasn't a random sampling and women with advanced cases of cancer weren't necessarily screened out of the study, some physicians have noted. The doctors also called into question the quality of the mammograms themselves, many of which were considered to be of poor or substandard quality, and therefore may have prevented early detection of smaller tumors.

The American Cancer Society still strongly endorses mammography as an effective means of screening for cancers in women over 40. They credit mammography, when done in conjunction with a thorough clinical breast exam (CBE) by a physician, for an increase in early detection and survival rates among women in this country.

As for the Shanghai study, despite the seemingly negative outcome, researchers did conclude that BSE can be an effective means of screening for breast cancer if it is properly taught and administered, and if it is followed up with an examination by a physician or a mammography screening. If nothing else, doctors have concluded, breast self-exam is a helpful tool for building awareness among women of general breast health.

Assessing Your Risk

The first thing every woman needs to do is assess her own personal risk for developing breast cancer. The American Cancer Society breaks down risk factors into two categories, those that are invariable (meaning they cannot be changed), and those that are variable.

Invariable Risk Factors

You have the greatest risk for breast cancer if you:

  • Are a woman
  • Are over age 45
  • Are a white woman
  • Have a genetic predisposition for the disease -- that is, you have inherited the BRCA1 or BRCA2 gene.

  • Have a mother or sister (or both) with the disease
  • Had a previous diagnosis of breast cancer
  • Have had repeated breast biopsies
  • Received repeated radiation treatments or chest X rays from puberty through childbearing years
  • Began menstruation before age 12 or menopause after age 50

Variable Risks

You have an increased risk for breast cancer if you:

  • Are a heavy drinker
  • Are obese
  • Lead a sedentary lifestyle
  • Eat a high-fat, low-fiber diet
  • Live in an urban area
  • Have been on HRT or oral contraceptives for 5 years or longer
  • Had your first full-term pregnancy after age 30
  • Have no children

Having any combination of these risk factors doesn't necessarily mean a woman will develop breast cancer, just that she must be more vigilant about it. However, vigilance is important for all woman, since 70 percent of all women diagnosed with the disease never exhibit any of these risk factors.


So What's A Woman To Do?

There is a saying in football that a great offense is the best defense, and when it comes to breast cancer, early detection is a woman's best defense. To this end, every woman has three recommended options to help screen for breast cancer. They are:

Breast self-exam -- this is a manual exam women perform monthly. Doctors suggest performing BSE after each menstrual period when premenstrual changes in the breast won't yield misleading results.

Who's the best candidate: All women over the age of 20 should perform this monthly exam.


Clinical breast exam -- this is a thorough manual examination of the breasts administered by a woman's physician, nurse practitioner, or an ob-gyn during an office visit.

Who's the best candidate: All women 20 to 39 should have a CBE every three years. After age 40, women should have a yearly CBE.

Mammography -- this is a specialized diagnostic test administered by a radiologist using X rays to detect tumors in breast tissue.

Who's the best candidate: All women over 40 should get yearly mammograms. Women under 40 with a family history of breast cancer or a previous breast cancer diagnosis should also have yearly mammograms.

There is some debate as to whether younger women should have yearly mammograms. The main concern is that repeated exposure to low-dose radiation can increase a younger woman's risk for the disease later in life. Additionally, younger women tend to have denser breast tissue. Mammography X rays cannot always penetrate this denser tissue and small tumors may not be detected.

Alternative options for younger women to consider include:

  • Breast ultrasound


  • MRI


Originally written for, October 2002.

The information on this Web site is designed for educational purposes only. It is not intended to be a substitute for informed medical advice or care. You should not use this information to diagnose or treat any health problems or illnesses without consulting your family doctor. Please consult a doctor with any questions or concerns you might have regarding your or your loved one's condition.