Impact of clinically unsuspected venous thrombotic events on CVC removal and survival in pediatric cancer patients: A population-based study from the Maritimes, Canada.

Venous thromboembolism (VTE) is a well-recognized complication in pediatric cancer patients. We aimed to determine the frequency of central venous catheter (CVC) removal and survival impact of children with cancer who develop VTE. After ethics approval, a retrospective population-based study of cancer patients less than 21 years between 2005 and 2020, in the Maritime Provinces Nova Scotia, New Brunswick, and Prince Edward Island was conducted. Clinical data was collected from hospital charts and online medical records. Data on demographics, cancer diagnosis and treatment, diagnosis of VTE, use of CVC, were assessed. Kaplan-Meier survival curves were computed and compared among study groups. This study included 770 patients with a male to female ratio of 1.1:1. There were 49 patients with symptomatic VTE, 49 patients with clinically unsuspected VTE, and 671 patients with no VTE. There were 15 (1.9%) non-CVC-symptomatic (ncsVTE), 34 (4.4%) CVC-symptomatic (csVTE), 40 (5.2%) non-CVC-clinically unsuspected (ncuVTE), 9 (1.2%) CVC-clinically unsuspected (cVTE), and 671 (87%) no VTE patients. The mean number of CVCs required during treatment was significantly higher among patients with VTE (p < 0.001). Both symptomatic and clinically unsuspected VTE required significantly more CVCs compared to no VTE patients (p < 0.001 and p = 0.049 respectively). Kaplan-Meier survival curves showed ncsVTE patients' survival was significantly reduced compared to all other patients (p < 0.001). This study demonstrates that pediatric oncology patients with ncsVTE have significantly lower survival. This suggests that ncsVTE may be a biomarker for increased disease burden. This study also demonstrated that clinically unsuspected VTE had significantly more CVCs placed during treatment compared to patients without a VTE, indicating the need for better screening.