If the Internet buzz about a pain-free, radiation-free alternative to mammography sounds too good to be true, there's a reason for that.
Breast thermography — recently touted in the Huffington Post as the "best breast test" by Oprah favorite Dr. Christiane Northrup — has not been proven effective for routine breast cancer screening in a large-scale, randomized study, experts say. The FDA has not approved it for that purpose and in 2009 issued a warning letter accusing an Idaho health care provider of marketing thermography as a mammogram replacement.
"The bottom line is that the proven technology for screening for breast cancer is X-ray or digital mammography. And that is the only proven technology," says Robert Smith, director of cancer screening for the American Cancer Society.
Northrup, who wrote in the Huffington Post that "many (doctors) believe that a mammogram is the best test for detecting breast cancer early . . . but it's not," responded to a request for comment with an e-mail saying, in part, "Thermography has been shown to pick up abnormalities in the heat in the breast many years before a lesion would likely show up in a mammogram. The ideal is to use both technologies when appropriate."
Breast thermography uses infrared cameras to detect subtle heat elevation associated with tumors, which tend to have more blood flow and higher metabolic rates than normal tissue. Considered promising in the 1960s, thermography fell out of favor with doctors in the '70s when a large study found it detected only 39 percent of breast cancers, while mammography picked up 78 percent.
Thermography advocates argue that the technology has improved vastly since then.
A small study of thermography as a supplement to mammography, published in the American Journal of Surgery in 2008, found it has an impressive 97 percent sensitivity rate, meaning it correctly identified 97 percent of the women who had cancer. Unfortunately, its specificity rate, the proportion of women correctly identified by the test as not having cancer, was a disappointing 44 percent. (Mammography has a sensitivity rate ranging from 77 to 95 percent and a specificity rate from 94 to 97 percent.)
In a 2009 commentary in Minnesota Medicine, Gregory Plotnikoff and Carolyn Torkelson wrote that thermography holds promise as a supplement to mammography — it's FDA approved for that — and called for more study. But they raised concerns that some consumers may think of it as mammogram replacement, which "could raise public-safety issues." And they noted thermography is a fragmented industry with no widely accepted professional standards.