Program: Oral and Poster Abstracts
Session: 331. Pathophysiology of Thrombosis: Poster I
Aims: Establish incidence of sVTE and identify risk factors associated with sVTE in pediatric cancer patients.
Methods: All pediatric cancer patients in the 3 Maritime Provinces of Nova Scotia, New Brunswick and Prince Edward Island are treated at IWK Health Center (IWK) in a shared care model. This provides a population-based cohort of pediatric cancer patients from the Maritimes. After ethics approval, all pediatric cancer patients treated at the IWK from 1995 to 2014 with sVTE were identified through a conceptual framework as follows. Clinical (including sVTE) and laboratory data was extracted from the: (i) Pediatric oncology hospital database (ii) Provincial Cancer in Young People registry (iii) Electronic medical records (iv) Pharmacy database (v) IWK Central Venous Access Database and (vi) Hospital health records. After extraction, data from all sources was amalgamated and cross-verified. SPSS version 21 was used for statistical analysis.
Central veins were defined as veins including and proximal to the axillary vein in the upper extremity and femoral vein in the lower extremity. sVTE was defined as radiologically documented VTE with at least one sign/symptom directly associated with VTE. Patients with VTE during relapsed disease and those with asymptomatic/incidentally diagnosed VTE were excluded from analysis.
Results: Forty-seven (4.356±0.01%) of the 1079 patients had sVTE. The mean age at diagnosis for sVTE patients was 10.142 years. The mean age at diagnosis of the remaining patients (n=1032) was 7.451 years. The difference in the mean ages in the 2 categories was statistically significant (p=0.001). The gender ratio was M:F: 1.765:1 in patients with sVTE as compared to M:F: 1.123:1 in the remainder of the patients (p=0.336).
Central veins were the most common location for sVTE (72.3%, n=34). Other less common locations included 1 each of sinovenous, mesenteric, cardiac, renal vein thrombosis and pulmonary embolism.
On univariate analysis for risk factors, age > 10 years at diagnosis (P = 0.021), type of cancer (P = 0.028) and non-O blood group (P = 0.043) were associated with sVTE, while gender (p=0.336) and use of asparaginase (p=0.663) were not.
On multivariate analysis, age > 10 years at diagnosis (odds ratio [OR]: 1.737 [1.066–2.831], p=0.027), and type of cancer (non-brain tumor; OR: 11.154 [1.527-81.451], P=0.017) were associated with sVTE. The association of non-O blood group with sVTE trended towards significance (OR: 1.886 [0.962–3.695], p=0.065) likely due to small numbers and difficulty identifying sVTE retrospectively.
Conclusion: In a large population-based cohort of patients, we established incidence of sVTE in pediatric cancer patients. The study identified that sVTE occur in central veins in almost 3/4th of the patients. As well, we evaluated easily available and independent risk factors for sVTE in pediatric cancer patients. Further larger prospective and multicenter studies are needed to validate these observations and develop a risk prediction model for sVTE in pediatric cancer patients.
Disclosures: No relevant conflicts of interest to declare.
See more of: Pathophysiology of Thrombosis
See more of: Oral and Poster Abstracts
*signifies non-member of ASH