The luteal heat cycle of the breast in disease.

Wearing a special thermometric brassiere, selected women self-measured their breast surface temperature. These measurements were made during one hour each evening at home for one menstrual cycle under standard conditions of overclothing and room temperature. To stage their cycle they also collected daily samples of saliva in their freezer for immuno-assay of progesterone concentration in the laboratory. A total of 82 women participated, most having young families. This total included four groups, a control group (N = 25) and three 'disease' groups, namely: family history of breast cancer (14); benign breast disease (12); and a 'cancer-associated' group (31) who had had previous cancer surgery. A significant breast temperature rhythm with a period at or about 28 days was found not only in the controls but also in the three groups of breasts designated 'disease'. Nevertheless, consistent rhythm abnormalities were found in all the disease groups. Most evident was a hyperthermia throughout the cycle, a reduction in the rhythm amplitude, and a tendency for the breast temperature rhythm to be manifest 1-2 days earlier in the menstrual cycle.