The risk of venous thromboembolism is increased throughout the course of malignant glioma: an evidence-based review.
BACKGROUND
Venous thromboembolism (VTE) frequently complicates the course of patients with cancer, and there is evidence to suggest that patients with brain tumors are at particularly high risk. The objective of this methodology-based literature review was to quantify the rate of incidence of VTE in patients with malignant glioma and to determine the factors that predict an increased risk of this complication.


METHODS
Studies meeting predefined inclusion criteria were evaluated independently on an eight-item methodology index by three raters. Authors were contacted to resolve ambiguities. The results of the studies were summarized and the incidence rate of VTE within the early postoperative phase and during extended follow-up were reported separately.


RESULTS
Within 6 weeks after surgery the incidence rate of deep venous thrombosis (DVT) ranged from 3% to 60%, varying with the prophylaxis regimen used, the method of diagnosis, and the study design. Beyond 6 weeks postoperatively, the rates of DVT ranged from 0.013 to 0.023 per patient-month of follow-up. The single study with no significant methodologic deficiencies found a 24% rate of incidence of symptomatic DVT over the 17 months of follow-up beyond the first 6 postoperative weeks. In 6 studies the presence of leg paresis, histologic diagnosis of glioblastoma multiform, age >/= 60 years, large tumor size, use of chemotherapy, and length of surgery > 4 hours were identified as possible risk factors.


CONCLUSIONS
The incidence of VTE is high throughout the course of malignant glioma. A randomized, controlled trial is needed to clarify whether the benefits of long term anticoagulant prophylaxis outweigh the risks and costs of such therapy.
Department of Medicine, Sunnybrook and Women's College Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
L C
LC
Marras
W H
WH
Geerts
J R
JR
Perry
D000925:Anticoagulants / Q000627:therapeutic use; D001932:Brain Neoplasms / Q000150:complications* / Q000601:surgery; D003625:Data Collection; D005910:Glioma / Q000150:complications* / Q000601:surgery; D006801:Humans; D011184:Postoperative Period; D011446:Prospective Studies; D012189:Retrospective Studies; D012307:Risk Factors; D020246:Venous Thrombosis / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control
D000925:Anticoagulants