Age at cancer diagnosis, non-O blood group and asparaginase therapy are independently associated with deep venous thrombosis in pediatric oncology patients: A risk model.

INTRODUCTION: Pediatric oncology patients are at increased risk for deep venous thrombosis (DVT). Determining the sub-population of children at increased DVT risk is critical for optimum clinical management. Therefore, the aim of the current study was to identify clinical risk factors for DVT which are easily identifiable at cancer diagnosis.

MATERIALS AND METHODS: A Canadian multicenter case control study in survivors of childhood cancer. Survivors who had DVT (Cases) while being treated for pediatric cancer where matched by center with a minimum of two survivors who did not experience DVT (Controls). Clinical information including age at diagnosis, type of cancer and chemotherapy were collected. Genotyping of blood group was done by single nucleotide polymorphisms analysis.

RESULTS: 218 subjects were recruited at 4 Canadian pediatric centers. Multivariable analysis demonstrated 3 significant variables (reported as Odds Ratio (OR), (95% CI), p value): age at diagnosis p<0.001, non-O blood group OR 2.6 (1.3-5.2) p=0.005 and asparaginase treatment OR 2.4 (1.2-4.8) p=0.011. In order to optimise clinical utility, we reanalysed the study data with age at diagnosis categorised into four subgroups 0-≤2years, >2-≤7years, >7≤10years, >10years. A significant association with DVT were seen in children 0-≤2years (OR 3.1 (1.1-8.3) p=0.026) and >10years (OR 3.8, 1.7-8.5 p=0.001). Significant associations with DVT remained for non-O blood group, OR 2.2 (1.2-4.4) p=0.016 and asparaginase treatment, OR 2.1 (1.1-4.0) p=0.027. The value for the clinical risk model receiver operating characteristics curve was 0.67.

CONCLUSIONS: We have shown 3 independent risk factors for DVT in childhood cancer.