Thrombotic complications in children with haematologic malignacies

The association of mediastinal mass in the formation of thrombi in pediatric patients with non-lymphoblastic lymphomas

BACKGROUND

Children diagnosed with cancer are at a significantly higher risk of developing a thrombotic event (TE) compared with the general population. The rarity of these events makes it difficult to discern the specific risk factors; however, age, sex, presence of central venous lines, inherited thrombophilia, and mediastinal mass may play a role. The primary aim of this study is to identify prognostic characteristics of children diagnosed with non-lymphoblastic lymphomas associated with a greater risk of developing a TE early on in their disease, with an increased focus on mediastinal mass characteristics.

METHODS

Retrospective chart review of pediatric patients diagnosed with non-lymphoblastic lymphoma between 2004 and 2014 at St. Jude Children's Research Hospital.

RESULTS

TE occurred in 8.5% (n = 28/330) of individuals at a median of 21 days from the diagnosis of a non-lymphoblastic lymphoma, with 60% of TEs occurring within 30 days of diagnosis. Of the variables evaluated, only presence of a peripherally inserted central catheter (odds ratio [OR]: 3.14 [95% CI: 1.24-7.98; P = 0.02]) and degree of superior vena cava (SVC) compression of > 25% increased the odds of developing a TE (OR: 2.2 [95% CI: 1.01-4.93; P = 0.048]).

CONCLUSION

Pediatric patients with non-lymphoblastic lymphoma are at increased risk of developing TEs. In contrast to previous studies, the presence of a mediastinal mass alone was not associated with a higher risk of TE, but individuals with a mediastinal mass with 25% or greater degree of SVC compression were more likely to develop a TE. This finding highlights a high-risk group of children who may benefit from prophylactic anticoagulation.

Activity levels of natural anticoagulant proteins in childhood acute lymphoblastic leukemia: relation to thromboembolic complications and treatment

Thromboembolism is a well recognized life-threatening complication in childhood acute lymphoblastic leukemia (ALL). Proper and early diagnosis of thromboembolism is of paramount importance to reduce mortality and morbidity. We evaluated antithrombin III (ATIII), protein C, protein S, and D-dimer in 60 children with ALL compared with 30 healthy controls, and patients were followed up for 12 months for detection of thrombotic complications. The relation between these natural anticoagulants and the development of thrombotic complications, as well as therapy was assessed to identify patients at risk of thromboembolism. ATIII, protein C, and protein S were significantly reduced (P < 0.001) with elevated D-dimer (P < 0.001) in patients with ALL compared with those in the control group. The incidence of thrombotic complications was 16.7%. Patients with thrombotic complications had significantly lower ATIII, protein C, protein S, and platelet count, whereas age, total leukocyte count, and D-dimer were increased compared with those without thrombosis (P < 0.05). Patients under chemotherapy had lower ATIII, protein C, and protein S levels with higher D-dimer compared with the newly diagnosed untreated patients (P < 0.05). ATIII and protein C were positively correlated (r = 0.573, P = 0.002), whereas both were negatively correlated with D-dimer (P < 0.001). ALL is associated with a state of hypercoagulability, which may be attributed to hemostatic derangement because of increased thrombin generation indicated by elevated D-dimer in association with decreased natural anticoagulants ATIII, protein C, and protein S. ALL children during induction/consolidation phase of chemotherapy are at high risk of developing thromboembolism complications and the prophylactic use of anticoagulant should be considered.

Rationale for a pediatric-inspired approach in the adolescent and young adult population with acute lymphoblastic leukemia, with a focus on asparaginase treatment

In the last two decades great improvements have been made in the treatment of childhood acute lymphoblastic leukemia, with 5-year overall survival rates currently approaching almost 90%. In comparison, results reported in adolescents and young adults (AYAs) are relatively poor. In adults, results have improved, but are still lagging behind those obtained in children. Possible reasons for this different pattern of results include an increased incidence of unfavorable and a decreased incidence of favorable cytogenetic abnormalities in AYAs compared with children. Furthermore, in AYAs less intensive treatments (especially lower cumulative doses of drugs such as asparaginase, corticosteroids and methotrexate) and longer gaps between courses of chemotherapy are planned compared to those in children. However, although favorable results obtained in AYAs receiving pediatric protocols have been consistently reported in several international collaborative trials, physicians must also be aware of the specific toxicity pattern associated with increased success in AYAs, since an excess of toxicity may compromise overall treatment schedule intensity. Cooperative efforts between pediatric and adult hematologists in designing specific protocols for AYAs are warranted.