Some Cancers May Just Go Away

A group of researchers who track breast cancer rates have proposed the controversial notion that some tumors found with mammograms might naturally disappear on their own if left undetected.

Dr. Per-Henrik Zahl and his colleagues examined invasive breast cancer rates among nearly 120,000 women age 50 to 64 who had a mammogram over a six-year period. They compared the number of breast cancers detected with another group of about 110,000 women of the same age who were screened just once at the end of the six-year period.

The researchers said they expected to find no differences in breast cancer rates -- but instead, they found 22 percent more invasive breast tumors in the group who had mammograms every two years. This raises the possibility that some cancers somehow disappear naturally.

Mammography and breast self-examination for tumors are standard methods used for early detection of breast cancer.

Sources:

  Archives of Internal Medicine November 24, 2008;168(21):2311-2316.

  New York Times November 24, 2008