Venous thromboembolism risk and management in women with cancer and thrombophilia

The Complexities of Metastasis

Therapies that prevent metastatic dissemination and tumor growth in secondary organs are severely lacking. A better understanding of the mechanisms that drive metastasis will lead to improved therapies that increase patient survival. Within a tumor, cancer cells are equipped with different phenotypic and functional capacities that can impact their ability to complete the metastatic cascade. That phenotypic heterogeneity can be derived from a combination of factors, in which the genetic make-up, interaction with the environment, and ability of cells to adapt to evolving microenvironments and mechanical forces play a major role. In this review, we discuss the specific properties of those cancer cell subgroups and the mechanisms that confer or restrict their capacity to metastasize.

Mecanismos do tromboembolismo venoso no câncer: uma revisão da literatura

Existe uma estreita relação entre o tromboembolismo venoso e o câncer. Pacientes com neoplasias apresentam maior incidência de eventos tromboembólicos em sua evolução clínica. A ocorrência desses eventos é considerada um marcador preditivo negativo nesse grupo de pacientes. Revisamos, então, a ativação dos mecanismos de coagulação neste grupo de pacientes. Trata-se de um processo complexo e multifatorial, relacionado tanto a características tumorais, estadiamento clínico, agressividade da doença e sítios tumorais, dentre outros. Novos biomarcadores vêm sendo pesquisados ao longo dos anos na tentativa de correlacioná-los ao risco trombótico, visando uma intervenção que melhore a evolução clínica desses pacientes oncológicos.

Male mice have increased thrombotic potential: sex differences in a mouse model of venous thrombosis

INTRODUCTION

Our objectives were to characterize sex differences during venous thrombosis, using the electrolytic inferior vena cava model of the disease.

MATERIALS AND METHODS

Male and female C57BL/6 mice (6-8 weeks) underwent inferior vena cava thrombosis. Time points included 6 hours, day 2, day 6, and day 14 post surgery, along with surgically naïve true controls and surgical shams. Analyses included thrombus weight, vein wall morphometrics, vein wall protein and gene expression for P-selectin, interleukin-1β, and tumor necrosis factor-α; hematology, soluble P-selectin, and plasma microparticle tissue factor activity assays.

RESULTS

Male venous thrombi were significantly larger than females at days 2 (13.1 ± 1.0 vs. 6.8 ± 0.5 × 10(-3) grams, p < 0.01), 6 (10.4 ± 0.8 vs. 5.4 ± 0.5 × 10(-3) grams, p < 0.01) and 14 (6.3 ± 0.5 vs. 4.1 ± 0.3 × 10(-3) grams, p < 0.01). Both male and female mice exhibited significantly increased vein wall P-selectin at 6 hours, vs. true controls (p < 0.05). Males had increased vein wall interleukin-1β, versus females, at 6 hours (180.926 ± 24.596 vs. 60.417 ± 10.478 pg/mL, p < 0.05) and day 6 (76.966 ± 13.081 vs. 33.834 ± 4.198 pg/mL, p < 0.01). Males showed decreased tumor necrosis factor-α expression (-66 %) at 6 hours. Females had increased tumor necrosis factor-α expression at 6 hours (+541%) and day 6 (+539%). Both sexes demonstrated decreased peripheral platelets at 6 hours (p < 0.05), coinciding with thrombogenesis. Plasma P-selectin increased in both sexes, versus controls, through day 6 (p < 0.05).

CONCLUSIONS

Males had significantly larger venous thrombi than females. Sex differences in vascular anatomy and response to inflammation may influence thrombus formation in our mouse thrombosis model.

Hyperhomocysteinemia and the role of B vitamins in cancer

BACKGROUND

Patients suffering from malignancies have increased complications due to corresponding cardiovascular diseases and risk factor for the development of venous thromboembolism. Epidemiological studies have shown that increased homocysteine plasma concentration (hyperhomocysteinemia) is related to a higher risk of coronary heart disease, stroke, peripheral vascular disease and malignancies. Homocysteine (tHcy) is an intermediate sulfur-containing amino acid produced from methionine during processing of dietary proteins. The plasma homocysteine levels are strongly influenced by diet, as well as by genetic factors. Folic acid, vitamins B6 and B12 are dietary components which influence the plasma homocysteine levels the most. Several studies have found that high blood levels of B vitamins are related to the integrity and function of DNA, and, are at least related to lower concentration of homocysteine. Folate depletion has been found to change DNA methylation and DNA synthesis in both animal and human studies. Because of this critical role of folate, most studies including homocysteine have focused on these two actions.

CONCLUSIONS

Hyperhomocysteinemia proves to be the most common condition highly associated with both venous and arterial thrombosis in many cancer patients, while the associated pathophysiology has not been precisely established yet. Therefore, of current interest is the possible role of folate metabolism developing into a cancer initiating hyperhomocysteinemia. This review will discuss this possibility.

[Case-control study evaluating the incidence of hyperhomocysteinemia in cancer patients in an internal medicine department]

PURPOSE

Cancer is a cause of venous thromboembolism. However, the physiopathology remains unknown. Hyperhomocysteinemia could be a promoting factor.

METHOD

We built a case-control study of 65 patients followed for 2 years to compare levels of homocystéinémie in cancer bearing patients with that in matched cancer free control patients.

RESULTS

Fifty per cent of cancer bearing patients had significantly increased blood serum levels of homocystéine (P=0.006). This increase did not correlate with any deficiency in blood serum levels of folate or vitamin B12.

CONCLUSION

High levels of homocystéinémie could be linked to tumor proliferation.

Who should be tested for thrombophilia?

PURPOSE OF REVIEW

The purpose of this review is to identify on the basis of available data and expert opinions who would benefit most from screening for thrombophilia.

RECENT FINDINGS

Recent studies have clearly defined the risk of venous thromboembolism in members of families with inherited thrombophilia. Meta-analyses have shown the role of the most common thrombophilic conditions in increasing the risk of recurrent venous thromboembolism in carriers. Screening for thrombophilia in venous thromboembolism patients might help identify those at higher risk of recurrences even though it is unclear how this information can be of use in modifying their management. Thrombophilia seems to play a role in early fetal losses as also shown in women at their first intended pregnancy, which makes it interesting to screen women after only one bad pregnancy outcome.

SUMMARY

Screening for thrombophilia can be performed particularly in young patients with venous thromboembolism. Carriers of inherited thrombophilia are at increased risk of venous thromboembolism recurrences. Screening families of venous thromboembolism patients with thrombophilia allows the identification of still asymptomatic carriers who may benefit from thromboprophylaxis. This may be true of women in fertile age belonging to thrombophilic families. In thrombophilic women with pregnancy complications prophylaxis may be offered to prevent recurrences.

Catastrophic antiphospholipid (Asherson's) syndrome and genetic thrombophilic disorders in obstetrics

Catastrophic antiphospholipid syndrome (CAPS) (Asherson's Syndrome), is a life-threatening condition characterized by a rapidly progressive thromboses resulting in a multiorgan dysfunction syndrome (MODS), evidence of systemic inflammatory response syndrome (SIRS) in the presence of antiphospholipid antibodies. CAPS differs from the classic APS by predominantly affecting small vessels, involvement of unusual organs, rapid onset of MODS, and the development of acute respiratory distress syndrome (ARDS) in 25% of patients, which is a feature of SIRS. Obstetric-related multiorgan failure may be a feature of a subset of CAPS more frequently than was previously thought. Patients with obstetric complications should be tested for antiphospholipid antibodies and genetic thrombophilia in order to institute early prophylaxis. Low-molecular-weight heparin is the drug of choice for preventing obstetric complications and CAPS due to its anticoagulant and anti-inflammatory properties.