Last Wednesday, right before the four-day Thanksgiving holiday weekend, as I was far more interested in preparing to have family over the next day than in what was going on in the medical news or the blogs, the results of a most fascinating study hit the news. In Medscape, the title of the news report was Mammography Study Suggests Some Breast Cancer May Spontaneously Regress; on WebMD, the story ran under the title Can Breast Cancer Disappear?; on Medical News Today, Mammograms May Identify Cancers That Would Otherwise Just Regress by Drs. Per-Henrik Zahl, Jan Maehlen, and H. Gilbert Welch. Not surprisingly, the study found its way out of the medical news and into mainstream media outlets as well, given how provocative the findings seemingly are. From the Medscape report on this study:
A mammography study from Norway has come up with the controversial proposal that one fifth of breast cancer detected on screening may spontaneously regress. But there is no easy way to verify whether this is the case, say experts.
The study was published in the November 24 issue of the Archives of Internal Medicine. It found that the cumulative incidence of invasive breast cancer in a cohort of women, aged 50 to 64 years, who received 3 mammograms over 6 years was 22% higher than in a control group of age-matched women who received only 1 mammogram at the end of a 6-year period.
In their review of possible explanations for the difference in the breast cancer rates between the 2 groups — which had similar risk factors for breast cancer — the researchers write that the “natural course for some screen-detected breast cancers may be to spontaneously regress.”
“I anticipate that many clinicians will react negatively to the possibility of spontaneous regression, said coauthor Jan Maehlen, MD, PhD, professor of pathology at the Ulleval University Hospital, in Oslo, Norway, in an interview with Medscape Oncology.
Before I discuss the study itself, let me briefly discuss why clinicians may have a bit of a problem with the implications of this study, if they accurately reflect the biology of breast cancer.