(RxWiki News) Screening recommendations for breast cancer continue to change. A new study now suggests that older women do not need to be screened as often as younger women. A breast cancer screening expert questions those conclusions.
Breast cancer screening every two years was just as beneficial as annual screens for women between the ages of 66 and 74, according to recent research. Researchers concluded biennial mammography also cut down on the harms of false positive results that indicate the presence of cancer which additional tests disprove.
However, Daniel B. Kopans, MD, professor of radiology at Harvard Medical School and senior radiologist of the Breast Imaging Division at Massachusetts General Hospital, questions the study design and its conclusions.
"Talk to your doctor about a breast cancer screening schedule that works for you."
The lead author of the study was Dejana Braithwaite, PhD, a University of California San Francisco assistant professor of epidemiology and biostatistics. The study involved data collected on 2,993 older women with breast cancer and 137,949 women without breast cancer from 1999 to 2006. The women in the study ranged in age from 66 to 89.
In a statement about the research, Dr. Braithwaite said, “Screening every other year, as opposed to every year, does not increase the probability of late-stage breast cancer in older women. Moreover, the presence of other illnesses such as diabetes or heart disease made no difference in the ratio of benefit to harm."
The study found no difference in the diagnosis of late-stage cancers between women screened every other year and those screened once a year.
Dr. Kopans questions the reason why the screening schedule was different among the two groups. “The fundamental problem is that these are likely distinctly different populations. These women were not randomly assigned and the authors provide no information as to why some women were screened annually and others were screened every two years. It is likely that the women screened annually were considered to be at higher risk of developing breast cancer while women screened every two years were likely considered to be at lower risk and therefore not recommended for more frequent screening,” he said.
The number of false positive results was nearly double among women ages 66 to 74 – 48 percent among those screened annually versus 29 percent among the biennial group.
Dr. Kopans also questions this finding. “Women recalled from screening should not be considered 'false positives.' They are not recalled because the radiologist interprets the findings as cancers that proved to not be cancer, but rather findings on a mammogram that raise the concern of the radiologist who requests additional evaluation. The vast majority of these recalls amount to a few additional mammographic pictures or perhaps an ultrasound to resolve the issue. Only approximately 1 to 2 percent of women screened are recommended to have a needle biopsy using local anesthesia and approximately 30 to 40 percent of these women will be diagnosed with breast cancer, which is a high yield,” Dr. Kopans told dailyRx News.
"Women aged 66 to 74 years who choose to undergo screening mammography should be screened every two years," said senior author Karla Kerlikowske, MD, a professor of medicine at UCSF and a physician at the UCSF-affiliated San Francisco VA Medical Center. "They get no added benefit from annual screening, and face almost twice the false positives and biopsy recommendations, which may cause anxiety and inconvenience."
Dr. Kopans disagrees. “The fundamental question is not answered or even addressed. If the groups are comparable (which is unlikely), these results suggest that breast cancers did not grow over the extra year among women in this trial who were screened every two years compared to those screened annually. I suspect that cancers do grow, and these results are based on biases introduced by the study design and not the fact that annual screening is not more efficacious than biennial.”
This study was published February 5 in the Journal of the National Cancer Institute. The study was funded by the National Cancer Institute of the National Institutes of Health, the National Cancer Institute-funded Breast Cancer Surveillance Consortium, the American Cancer Society and the Agency for Healthcare Quality and Research.