Thrombogenesis in patients with breast cancer treated with adjuvant CMF protocol

Abstract EN

This study was planned to estimate prothrombin time (PT), partial thromboplastin time (PTT), protein C and protein S before and after 6 cycles of adjuvant CMF regimen in patients with breast cancer to determine the effect of this regimen on these coagulation parameters (mainly protein C and protein S) and its role in the hypercoagulability state among these patients.

Forty patients with operable breast cancer were included in the study and were subjected to initial clinical examination, intensive laboratory investigations and routine radiological studies to exclude patients with metastatic breast cancer and those with increased risk for thromboembolism.

All patients were treated with adjuvant CMF regimen for 6 cycles every 21 days, two blood samples were obtained one before starting the adjuvant CMF and another one after the completion of 6 cycles of this regimen to estimate prothrombin time (Modified Quick technique) [2], partial thromboplastin time (Modified Proctor and Rappaport technique) [13], protein C and protein S (by coagulometric assay, using fibrintimer) [18, 19].

We found that the mean of the four coagulation parameters were statistically significantly decreased after CMF chemotherapy (p = 0.017, 0.001, 0.001, 0.001 respectively).

12 patients out of 40 showed a significant decrease below normal range in prothrombin time and protein C after adjuvant CMF (p = 0.01 and 0.001 respectively).

Also, 16 patients out of 40 showed significant decrease in protein S below normal range (p = 0.001), but as regard PTT, no patient showed decrease below normal range after this regimen.

This decrease in the natural anticoagulants protein C and protein S might indicate that there is increased liability for thromboembolism after adjuvant CMF, although non of the patients manifested any thromboemoblic complications.

So, we can conclude that, patients with decrease in protein C and protein S after chemotherapy should be monitored closely to prevent thromboemoblic complications, patients with heterozygous protein C deficiency or factor V leiden must be excluded for adjuvant chemotherapy by CMF and treated by another protocol and lastly large scale of patients and more extensive coagulation studies before, during and after chemotherapy may clarify the problem.