SAN DIEGO — Children with cancer had worse outcomes if they had symptomatic venous thrombotic events, according to results of a population-based study conducted in the Maritimes, Canada presented at the ASH Annual Meeting and Exposition.
“There is a significant body of data published on symptomatic venous thrombotic events [sVTE], which are a well-recognized complication in pediatric cancer patients,” Ketan Kulkarni, MD, pediatric hematologist/oncologist at IWK Health Centre in Halifax, Nova Scotia, said during his presentation.
“There are a lot of data on the incidence of sVTE and their risk factors.
However, the association of sVTE with survival outcome in pediatric cancer patients is not well studied, and it’s not clear what the association is.”
Researchers used a database of patients treated at IWK Health Centre — which treats all pediatric oncology patients from Nova Scotia, New Brunswick and Prince Edward Island — to evaluate OS and EFS outcomes related to the incidence of sVTE in 936 children.
“All of the pediatric cancer patients in the Maritimes are diagnosed and treated at IWK Health Centre in a shared-care model of 25 regional and provincial hospitals,” Kulkarni said.
“This is pretty much a population-based cohort of pediatric cancer patients, and that helps us significantly in terms of the strength of the data, because it is likely our data are representative of the total oncology population from the region.”
Researchers supplemented data from the hospital database with data from the Provincial Cancer in Young People registry, hospital health records and pharmaceutical databases to identify all patients with sVTE.
Forty-seven children (5.02 ± 0.01%) had sVTE, defined as radiographically documented VTE with at least one sign or symptom of VTE.
The mean age of diagnosis of children with sVTE was 10.1 years, and most were boys (ratio of boys to girls, 1.8:1).
The most common cancers in these children were leukemia (n = 17; 36.2%), lymphoma (n = 9; 19.1%), sarcoma (n = 9; 19.1%), brain tumor (n = 1; 2.1%) or others (n = 11; 23.4%).
The most common location of sVTE was central veins (n = 34; 72.3%).
Seventeen of the patients with sVTE died, compared with 133 patients without sVTE (36.2% vs. 15%; P = .001).
Estimated mean OS was 133.1 ± 33.6 months in children with sVTE compared with 163.7 ± 4.8 months in those without sVTE (P less than .0001). Researchers also estimated that patients with sVTE were significantly less likely to achieve 5-year OS (P = .007).
Estimated mean EFS also was inferior in patients with sVTE (112.7 ± 31 months vs. 148.7 ± 5.9 months; P less than .001).
“We think that patients possibly at higher risk for death are more likely to be diagnosed with VTE,” Kulkarni said.
“None of these deaths were directly related to VTE; we looked at survival from a standpoint of cancer, and not VTE–associated mortality.
We do think there is a need to understand the drivers of the association of sVTE and inferior survival outcome so factors other than VTE–associated mortality are involved.” – by Alexandra Todak