Mammograms save many lives, but screening for breast cancer also produces many false positive results — leading to unnecessary, invasive testing, not to mention untold anxiety for women and their loved ones. A recent study has identified yet another concern. In Norway, investigators found that women who underwent screening mammography were significantly more likely to be diagnosed with breast cancer than those who did not get screened, leading to the possibility that some breast cancers disappear spontaneously on their own without treatment. It’s an intriguing finding, given how much time, cost and anxiety is associated with diagnosing breast cancer — even more so when you consider how many women might not require aggressive treatment, including potent drugs, powerful radiation and painful, disfiguring surgery, for cancers that might disappear on their own.
I spoke with one of the country’s leading breast cancer authorities, Susan Love, MD, a clinical professor of surgery at UCLA’s David Geffen School of Medicine, founder of the Dr. Susan Love Research Foundation (www.dslrf.org) and author of Dr. Susan Love’s Breast Book. She called the study “extremely encouraging,” noting it might someday enable researchers to identify which types of breast cancers require treatment and which can simply be monitored… but she cautions that we’re not there yet. At present, women should continue to get their regularly scheduled mammograms.
In the study, investigators compared the number of breast cancers detected in two groups of Norwegian women, ages 50 to 64 (over 100,000 participants), who underwent mammography screening. One group received three mammograms between 1996 and 2001 as part of a new national screening program. The other group had just a single screening in 1997.
Theoretically, these comparable groups should have the same number of cancers, says Dr. Love. Yet that did not prove to be the case. Researchers found 22% more breast cancers in the women who underwent more frequent mammograms. This raises the possibility that left untreated, these tumors might have spontaneously regressed. It’s not such a far-fetched theory, given that scientists already know of at least one other cancer — a rare childhood cancer called a neuroblastoma — that is known to regress without treatment in as many as 7% of cases that are detected through screening.
These results were published in the November 24, 2008, issue of the Archives of Internal Medicine. Though the study results raised a hubbub, Dr. Love didn’t find them surprising and said she suspects the type that disappears on its own might be one called “almost normal” breast cancer because it is so non-aggressive. “It’s just a hunch though,” she notes — agreeing with the researchers that further study is required.
Just as “watch and wait” is a treatment strategy for some prostate cancers, perhaps research will identify certain types of breast cancers that can safely be approached in the same way, says Dr. Love. Looking ahead, she notes that this and similar studies may even lead to changes in what’s considered “cancer.” It may be that in some people, some groups of abnormal cells may appear that will never develop into a life-threatening tumor and should not be referred to — or more importantly treated as — cancer.
As things now stand, though, it’s impossible to predict whether a tumor will spontaneously regress, nor will that likely be possible anytime soon. For now, the American Cancer Society (www.cancer.org) recommends that women get an annual mammogram beginning at age 40. Women at high risk — those with a family history of breast cancer or who test positive for a genetic mutation in BRCA 1 or BRCA 2 genes — should also get an MRI. If you are uncertain, consult your physician to determine your risk level.
