Thrombophilic Genetic Mutations Have No Impact in the Pathogenesis of Thromboembolism in Gastro-Intestinal Cancer Patients.

Deep venous thrombosis and pulmonary embolism are well recognized and feared complications in cancer patients, with a considerable impact on the overall survival and the quality of life. During the last years many prothrombotic genetic mutations have been described, of these the most common are: Factor V Leiden, prothrombin G20210A gene mutation and the C677T mutation in the 5,10 methylenetetrahydrofolate reductase (MTHFR) gene. Aim of this study was to asses the impact of these thrombophilic gene mutations on the development of VTE (Venous ThromboEmbolism) in patients with gastro-intestinal neoplasms. Moreover, we have tried to determine whether or not the C677T polymorphism of the MTHFR gene was associated with a higher toxicity during chemotherapy with antimetabolites such as 5-FU. From October 2002 to June 2004 48 patients (aged more than 18 years) not assuming anticoagulant therapy, with a new histopathologic diagnosis of gastro-intestinal cancer and no known hematologic or immunologic diseases were investigated by standard polymerase chain reaction techniques for the presence of the above thrombophilic gene mutations. Of the 48 tested patients, a homozygous or heterozygous Factor V Leiden was present respectively in 1 and 3, while the G20210A Factor II mutation was observed in 6 patients (all heterozygous). The C677T mutation in the MTHFR gene allelic frequency in the studied population was 46%. A VTE was observed in 7/48 patients (14.5%) and none of these patients had Factor V Leiden or G20210A Factor II mutations while 4 had a C677T MTHFR mutation. Therefore, none of the thrombophilic genetic mutations studied was associated to the development of VTE in the cohort of gastro-intestinal cancer patients. On the contrary chemotherapy (P=0.007) and advanced inoperable disease (P=0.009) were the only risk factors statistically significant for the development of VTE. As for toxicity during chemotherapy with antimetabolites, it was present in 25% of patients with the C677T polymorphism of the MTHFR while none of the patients without mutation had a toxicity (P=0.06). In conclusion, thrombophilic genetic mutations have no effect on the development of VTE in gastro-intestinal cancer patients. Moreover, we confirm that chemotherapy and an advanced disease play an important role in the pathogenesis of VTE in cancer patients. Furthermore, patients carrier of the C677T mutation in the MTHFR gene have a higher risk (OR: 1.4; C.I. 95%: 0.88–2.24) of toxicity during an antimetabolites-based chemotherapy.