Circadian breast skin temperature rhythms: overt and occult benign and occult primary malignant breast disease.

Circadian variations of breast surface temperature have been measured in patients with overt or occult benign breast disease, or in those with occult breast cancer. Subjects were studied in a hospital ward environment well-controlled with respect to ambient temperature. Using manual techniques temperatures were recorded half-hourly for 96 hr from replicate sensors placed on quadrants of the left and right breasts inclusive of tumour areas and similar sites on the contralateral breast. Application of time series analysis failed to consistently demonstrate differences in values for the rhythm parameters for the tumour area and contralateral site. It was apparent, however, that the tumour area was generally associated with a reduced initial variance of the series in addition to a reduced percentage variance explained by a time series model with two rhythmic components when compared to the control site. These data suggest that efforts to identify early breast disease from signals of breast temperature should, at least, be directed to studies of temperature variance.