Effects of high dose medroxyprogesterone acetate treatment on antithrombin III and other plasma proteins in males with renal cell or prostatic carcinoma.

In 18 patients, 12 with renal cell and 6 with prostatic carcinoma treatment with high dose medroxyprogesterone acetate (MPA) significantly increased serum antithrombin III and haptoglobin concentrations. During treatment the proteins correlated with each others suggesting a response to similar regulatory mechanisms. Levels of orosomucoid, a1-antitrypsin, C1-inhibitor and von Willebrand factor did not change during treatment showing that the increase of haptoglobin was not due to an acute-phase response. The increased antithrombin III levels may have a favourable impact on the frequency of thromboembolic complications during treatment with MPA.