[Risk of thrombosis in irradiation of uterine cancer. A review with new results of studies].

Malignomas of the uterus predispose to thromboembolism. Local application of radium increases the activation of hemostasis. In newer examinations there are hints, that impairment to thrombocyte function and prostacyclin metabolism may have a pathogenetic meaning. Thrombocyte aggregation and prostacyclin sensitivity of thrombocytes have been examined in two groups of patients: 21 patients following hysterectomy because of endometrium cancer stage I, treated with one vaginal application for the vaginal cuff and 10 patients with cervical carcinoma Stage IIa-IIIb treated combined intrauterine-intravaginally. The first group was prophylactically treated with low-dose-heparin, the second one with acenocoumarol (Sintrom). A slight, but significant increase of thrombocyte aggregation by 4.8 per cent respectively 5.0 per cent could be observed in both groups. Prostacyclin sensitivity of thrombocytes (PST) was significantly reduced by 20 per cent before irradiation in all patients compared with patients without carcinomas. In cases of intravaginal radium application we saw immediately after removal of the radioactive source a further reduction of PST by 12.5 per cent. 24 hours later a significant decrease of PST by 18.5 per cent could be observed. Contrary to this no significant changes were induced by combined intrauterine and intravaginal radium insertion. Therefore reduction of PST may be interpreted as a possible change of thrombocyte function in vivo caused by irradiation. It may be likely that these disturbances of thrombocyte function combined with radiogenic vessel wall damages and plasmatic hypercoagulability are responsible for the high thromboembolic risk of radium therapy. These patients should be treated prophylactically. Probably the efficiency of this prophylaxis can be improved by additional application of selective inhibitors of thrombocyte aggregation or inductors of prostacyclin synthesis.