Some experts in the United States do not plan to change their practice of instructing women in BSE, however, and lead investigator David Thomas stresses the conclusions may not apply to women highly motivated to do the self-exams.
Thomas, an epidemiologist at the Fred Hutchinson Cancer Research Center in Seattle told United Press International the study has implications for BSE training programs. Governments, such as China's, are trying to prevent breast cancer deaths through broad-based programs in BSE where mammograms generally are not available.
Health officials should not "bother to push and conduct and to finance a huge BSE program in the general population," said Thomas. "It's highly unlikely that you would have any effect on breast cancer mortality."
The study results do not apply to a strongly motivated woman who wants to learn breast self-examination and is determined to be conscientious, Thomas said. "If a woman is going to practice breast self-examination she's got to do it well and she's got to do it frequently. If she isn't going to make that kind of commitment then she's probably wasting her time," he said.
"We have a falling death rate from breast cancer and we should be very careful before we change anything that has been associated temporally with that falling death rate," Clifford A. Hudis, chief of the breast cancer medicine service at Memorial Sloan-Kettering Cancer Center in New York City, told UPI. Hudis said he plans to keep instructing women in breast self-examination, even though the study appears "powerful and well-done."
Lillie Shockney, director of health education and outreach for the Johns Hopkins Breast Center in Baltimore, told UPI there are no plans to change clinical practice based on the Shanghai study. "Half of all the women we see have found their own lump," she said.
The Shanghai researchers cautioned women who choose to practice BSE should be informed its effectiveness is unproven and it could increase their chances of having a biopsy on a noncancerous tissue growth. BSE is no substitute for regular mammograms, they said.
The study enrolled 266,000 women factory workers in Shanghai and gave half of them intensive instructions in self-examination, including monthly reminders to practice the examinations, practice under medical supervision every six months for five years and receive additional training sessions at one and three years.
After 10 to 11 years, the death rates from breast cancer in both the instructed and uninstructed groups were the same: about one in 1000 women. In the half that received training there were 135 breast cancer deaths vs. 131 deaths in the group receiving no instruction. Mammograms are not widely used in China and detection depends on clinical exams and women noticing lumps in their breasts.
"This new study, and others, tell us that it's unlikely we can teach all women to do the exam that well," Russell Harris, co-director of the program on prevention at the University of North Carolina Medical School at Chapel Hill, told UPI.
The results will be published in the Oct. 2 issue of the Journal of the National Cancer Institute.
(Reported by Joe Grossman, UPI Science News, in Santa Cruz, Calif.)