Can Breast Cancer Disappear?
Study Shows Some Cancers Detected by Mammograms Regress on Their Own; American Cancer Society Disagrees
Breast Cancer Screening continued...
He says the results imply that as many as two out of three screenings detected lesions -- including invasive cancers and the noninvasive ductal carcinoma in situ (DCIS) -- may be pseudo cancers.
Maehlen expects the conclusion to spark debate. "The majority of the people in the field would be skeptical," he says.
As to which women might be more likely to have breast cancers that spontaneously regress, Maehlen says that is not known. "It could be the immune system is the cause for the disappearance of some cancers," he says, presumably with the healthiest immune systems most likely to fight off cancers.
Or, he says, it could depend on the biology of the individual cancer as to whether it regresses.
The American Cancer Society took issue with the thinking that cancer may regress on its own. "The conclusion that more than 1 in 5 invasive breast cancers is destined to regress without incident if not detected by mammography [the 22% figure cited in the study] is nothing more than an overreaching leap in logic," Robert A. Smith, PhD, director of cancer screening for the American Cancer Society, says in a prepared statement.
Other studies have found that "overdiagnosis" -- not the same as regression -- probably occurs in less than 5% of all screen-detected cancer cases if it exists at all, Smith says.
He says the benefits of regular mammograms far outweigh any limitations, such as false-positive results and "possibly a small rate of overdiagnosis."
The study has weaknesses, but also strengths, says Robert Kaplan, PhD, the Wasserman Distinguished Professor and chair of the department of health services at the University of California, Los Angeles School of Public Health, in an editorial accompanying the study.
As a result, he writes, "the findings should not be dismissed."
The study, Kaplan says, points out how little experts know about the natural history of breast cancer.
The concept of breast cancer spontaneously regressing is worth further study, Kaplan writes.