In this study, we provide evidence for the first time that patients with GCT who receive cisplatin-based chemotherapy are at a significantly higher risk of having a thrombosis in the subsequent 6 months compared with those with other cancers who received similar treatments. Moreover, the risk of having a thrombosis could be predicted in GCT patients using two simple factors: a high body surface area (>1.9

m
2) (or a high weight) and an elevated serum LDH before chemotherapy. Patients with no risk factor had a risk of thrombosis of 4% while those with at least one risk factor had a risk of 26%. These features were 0 and 17% respectively in a validation set of patients with GCT treated in a different institution. Morbidity and mortality were relevant in this population of young men who are likely to achieve a cure of their cancer. TEE consisted mainly in venous thrombosis, with arterial events being more rare.
A large number of TEE occurring in GCT patients have been published as case reports (
Doehn et al, 2000;
Koga et al, 2001;
Blokh et al, 2003;
Leslie et al, 2003; cases published before 2000 reviewed in
Weijl et al, 2000). In a British series of 333 patients with advanced GCT, the incidence of vena cava compression was 9.3%, of whom 29% had a thrombo-embolic complication and one patient died of pulmonary embolism (
Hassan et al, 1999). Two previous studies also underscored the apparent high risk of TEE in GCT patients receiving chemotherapy, although there was no control group in these studies (
Cantwell et al, 1988;
Weijl et al, 2000). In a series of 52 patients,
Cantwell et al (1988) reported 10 TEE (19%), including seven venous events, three arterial events, and one death. In another series of 179 patients,
Weijl et al (2000) reported 15 TEE (8%), including 13 venous events, two arterial events, and one death. Moreover, a recent study with a 10-year follow-up showed that GCT survivors are at a higher cardiac risk than controls in the long term (
Huddart et al, 2003). Therefore, based on our experience and previous publication, there is evidence that GCT patients have a three-fold higher risk of TEE (consisting mostly in venous events) during chemotherapy and soon afterwards, and that they have a two-fold higher risk of cardiac events in the long term.
The pathogenesis of TEE in GCT patients is not fully understood. Whether the causes are cancer related, treatment related, or both is still unknown. One weakness of our study was the relatively high number of parameters that were tested in univariate analysis compared to the limited number of patients (100). In the Weijl series, liver metastases and high doses of steroids (used as anti-emetics) were independent predictors of TEE, but these factors were not tested in a separate set of GCT patients (
Weijl et al, 2000). In our study, the fact that CGT patients had a much higher risk for TEE than non-GCT cancer patients, even though both received cisplatin-based chemotherapy, indicates that cisplatin itself is not the only risk factor for TEE, in contrast with previous hypothesis (
Icli et al, 1993). However, we can certainly not rule out a direct or indirect role of chemotherapy in the pathogenesis of TEE. Other drugs, in particular bleomycin (
Schwarzer et al, 1991) and etoposide (
Schwarzer et al, 1991;
Airey et al, 1995), as well as the traditional 5-day protocols used in GCT might favour the occurrence of TEE, either via immobilisation or the daily use of steroids. A high body surface area (or weight) was identified as a risk factor of TEE in our study. This may be due to a direct effect since obesity is a well-known risk factor of venous TEE (
Rosendaal, 1999). Alternatively, it may be due to an indirect factor related to chemotherapy since doses of chemotherapy drugs (except for bleomycin) are prescribed according to body surface area. Interestingly, hypercholesterolaemia has been suggested to be found more often in GCT survivors (
Gietema et al, 1992;
Raghavan et al, 1992;
Meinardi et al, 2000) and this may be a potential explanation for arterial TEE during chemotherapy for GCT. In contrast, a recent study did not find any correlation between cisplatin administration and lipid profile in GCT survivors (
Fenton et al, 2002).
Apart from the potential involvement of treatment-related factors, there is some evidence to support a direct contribution of GCT to the occurrence of TEE. For example,
Weijl et al (2000) reported that a number of GCT patients experienced a TEE even though they had not received anticancer treatment. Indeed, we have made similar observations. Moreover, human teratocarcinoma cell lines release plasma membrane vesicles with procoagulant properties (
Dvorak et al, 1983). Serum LDH is linked with tumour bulk and prognosis in advanced GCT (
Fossa et al, 1997;
IGCCCG, 1997) and we show in this study that this factor also predicts the risk of TEE. These findings indirectly support the role of GCT in the occurrence of TEE. Whether the secretion of LDH by GCT cells has a direct effect or is associated with the production of procoagulant factors is unknown.
In our opinion, the high incidence of TEE in GCT patients with either a high body surface area, a high serum LDH, or both, and who receive cisplatin-based chemotherapy is sufficient justification to prospectively evaluate the potential impact of thromboprophylaxis in these patients. However, this strategy needs to be cautiously balanced with the potential risk of thrombocytopenia (although usually mild) related to chemotherapy in patients with GCT. Recently, large studies have demonstrated that subcutaneous low-molecular-weight heparin can be safely used and reduces the risk of TEE in patients with acute medical illnesses (
Samama et al, 1999). Moreover, recent randomised trials have suggested that low-molecular-weight heparin may be safer than vitamin K antagonists and that they may also be better in reducing the risk of TEE recurrence in cancer patients (
Meyer et al, 2002;
Lee et al, 2003,
2005).