Studies on circadian periodicity of plasma 17-hydroxycorticosteroids (17-OHCS) in carcinoma of the breast.

Circadian periodicity of plasma 17-hydroxycorticosteroids (17-OHCS) was studied in 25 histopathologically proved breast cancer patients pre operatively and on the 9th postoperative day and in 15 healthy women under tropical conditions. A marked rhythm in plasma 17-OHCS concentration was noticed in healthy controls. The maximal concentration occurred at 06:00 followed by a consistent decline throughout the daytime, reaching a minimum at 00:00 with an amplitude statistically significantly different from zero and an acrophase around 08:56. The plasma 17-OHCS concentration was found to be elevated at all sampling hours in breast cancer patients, irrespective of the stage of the disease. However, the degree of elevation and disruption of rhythm was more pronounced in advanced sages, preoperatively, in comparison to other groups. Moreover, the values declined markedly at all collection hours after mastectomy, approaching usual values and rhythm characteristics on the 9th postoperative day.