According to a study of women factory workers in China, having women do breast self-examination (BSE) alone does not lead to fewer deaths from breast cancer, even when intense efforts are made to teach the women how to perform BSE properly. The study is reported in the October 2nd issue of the Journal of the National Cancer Institute (Vol. 94, No. 19: 1445-1457; 1420-1421).

But US experts still say a monthly BSE contributes to a woman's body awareness, making her alert to changes, and is a supportive method for a three-part early detection program, which should include mammography and clinical breast exam (CBE).

The study was done in Shanghai, from October 1989 through July 2000, and was reported by David B. Thomas MD, DrPH, from the Fred Hutchinson Cancer Research Center in Seattle, and colleagues from China and Norway.

Shanghai was a unique city in which to do this study. Women in Shanghai tend to work at a single factory throughout their work life, mammography is not available to them, and they receive almost all of their medical care through the factory.

The researchers trained a group of women to teach the factory workers BSE, and to follow-up with repeat education. About 133,000 women received the BSE training and monitoring, while another 133,000 women received only routine medical care, without instruction in BSE.

What made this study special was the number of women involved, and the ability to educate and follow the women so closely for so many years. Also, there was no mammography available during the study, so BSE was the sole method of detecting breast cancers.

Although the women who were trained in BSE were much better at performing the exams than the women who were not trained, the study did not show that the women who were trained lived longer or died less often from breast cancer.

However, women trained in BSE had more benign breast biopsies, and more biopsies in general than the women who had not been trained, the study found.

The researchers concluded that the teaching of BSE did not result in fewer deaths since the breast cancer was not diagnosed at a "less advanced stage of progression for appropriate therapy to have altered the course of the disease."

"For women in more developed countries with access to mammographic screening, the results of this trial should serve to emphasize that BSE is not a substitute for regular screening by mammography," said the researchers.

But they also cautioned that it is possible that motivated women, performing BSE between mammographic screenings may increase the benefits of a screening program. "It should be emphasized to such women that they must practice BSE regularly and with a high degree of proficiency," the authors concluded.

In the Shanghai study during the first five years, women practiced BSE under supervision about every four to five months (though urged to practice monthly on their own). This schedule "did not have an effect on breast cancer mortality," said the authors.

In an editorial which accompanied the report, Russell Harris, MD, MPH, and Linda Kinsinger, MD, MPH, from the department of medicine at the University of North Carolina in Chapel Hill, pointed out that it is difficult to learn how to perform BSE well.

They also noted that one of the striking changes over the past 25 years in the US in breast cancer "is the reduction in the size of lumps discovered by women themselves." Large lumps, said the editorialists, are much less common today than they were previously.

But Harris and Kinsinger say that it would have been harder to find out if BSE teaching decreased death from breast cancer, when used along with other methods of breast cancer screening such as mammography.

"Teaching BSE seems like a good idea: it sounds inexpensive, simple, and potentially applicable to people without access to mammography. It allows women to take charge of their own health and teaches them about their bodies," they said.

"But," Harris and Kinsinger continued, "the evidence is increasingly clear and difficult to ignore: BSE is more expensive than it first appears, it is difficult to learn to do well, and it is difficult to continue to do long term."

Most important, they said, is that it doesn't reduce a woman's chances of dying from breast cancer.

In conclusion, wrote Harris and Kinsinger, women should still be aware of the need to get medical advice if they discover a lump in their breast. And, instead of giving detailed instruction in how to do BSE, perhaps doctors should spend some extra time on doing a thorough clinical breast exam when a woman is seen in their office.

Robert Smith, PhD, director of cancer screening and Debbie Saslow, PhD, director of breast and cervical cancer at the American Cancer Society, said that further years of follow-up of the women in this study were needed. It may be too early to see a change in the death rate. "We would expect to see differences later on in the follow-up of the women in this study. We are not there yet," they said.

Current American Cancer Society recommendations for breast cancer early detection are:

• Breast self-exam should be performed monthly beginning at age 20. But BSE is only one part of a three-part early detection program, which should include mammography and clinical breast exam (exam performed by a medical professional).
• Mammography and clinical breast exam have the greatest impact on reducing breast cancer mortality. BSE’s role in early detection is a supporting, but important one.
• BSE contributes to awareness, helping women be alert to changes in their breasts and identify changes earlier. However, for women 40 and older, the greatest potential to save lives from breast cancer is through early detection with mammography.

Smith emphasized, "BSE teaches women what is normal for them. It provides a heightened sense of awareness, and lets them know there is something that needs to be brought to the attention of their doctor."

Saslow and Smith said the study didn't argue the value of finding breast cancers when they are smaller. The smaller a breast cancer when it is discovered, the better is the prognosis for the woman, they said.

Unlike in China, where mammography was not generally available to the women in this study, mammography is an important part of breast cancer screening in the US to help find cancer at an earlier stage.