[The half-life of iodine 131-labelled fibrinogen in cancer patients. Effects of heparin].

Sixty nine patients suffering from malignant tumours at different stages of their development underwent a kinetic study of fibrinogen 131I with external counting over the tumour and a study of haemostasis including P.D.F. The 1/2 T of fibrinogen 131I is shortened: 2.52 +/- 0.09 days (normal: 3.89 +/- 0.11 days.) The abnormality is proportional to serum P.D.F. levels (r=0.99). External counting demonstrated the uptake of labelled fibrinogen in the tumour. Heparine (15000 U/24h) restores the 1/2 T of fibrinogen to normal in 95 p. cent of cases. The results suggest the existence of a localised compensated intravascular coagulation process inside the tumour. Possible consequences of that phenomenon are discussed.