Breast cancers

Breast cancers may naturally regress

Researchers who tracked breast cancer rates in women proposed the controversial notion that some tumors found with mammograms might otherwise naturally disappear on their own if left undetected.

But experts expressed doubt about the findings and urged women to continue to get regular mammograms, saying this screening technique unquestionably saves lives by finding breast cancer early on when it is most treatable. They compared the number of breast cancers detected with another group of about 110,000 Norwegian women of the same age and similar backgrounds who were screened just once at the end of the six-year period. This raises the possibility that some cancers somehow disappear naturally, although there is no biological reason to explain how this might be, according to Zahl, whose findings were published in the Archives of Internal Medicine.

Mammography and breast self-examination for tumors are standard methods used for early detection of breast cancer, the leading cause of cancer deaths among women worldwide. The American Cancer Society estimated that about 465,000 women die of breast cancer globally each year, and 1.3 million new cases are diagnosed.

The researchers acknowledged many doctors might be skeptical of the idea but they cited 32 reported cases of a breast cancer regressing, a small number for such a common disease.