Circadian rhythm chaos: a new breast cancer marker.

Keith LG, Oleszczuk JJ, Laguens M.; Department of Obstetrics and Gynecology,
Northwestern University Medical School, Chicago, Illinois, USA.

The most disappointing aspect of breast cancer treatment as a public health issue has
been the failure of screening to improve mortality figures. Since treatment of latestage
cancer has indeed advanced, mortality can only be decreased by improving the rate of
early diagnosis. From the mid-1950s to the mid-1970s, it was expected that
thermography would hold the key to breast cancer detection, as surface temperature
increases overlying malignant tumors had been demonstrated by thermographic
imaging. Unfortunately, detection of the 1-3 degrees C thermal differences failed to bear
out its promise in early identification of cancer. In the intervening two-and-a-half
decades, three new factors have emerged: it is now apparent that breast cancer has a
lengthy genesis; a long-established tumor-even one of a certain minimum size-induces
increased arterial/capillary vascularity in its vicinity; and thermal variations that
characterize tissue metabolism are circadian ("about 24 hours") in periodicity. This
paper reviews the evidence for a connection between disturbances of circadian rhythms
and breast cancer. Furthermore, a scheme is proposed in which circadian rhythm
"chaos" is taken as a signal of high risk for breast cancer even in the absence of
mammographic evidence of neoplasm or a palpable tumor. Recent studies along this
line suggest that an abnormal thermal sign, in the light of our present knowledge
of breast cancer, is ten times as important an indication as is family history data.