Widespread Contraindicated Use of Bevacizumab in Elderly Patients
In a study reported in Journal of Clinical Oncology, Dawn L. Hershman, MD, MS, of Columbia University, and colleagues assessed the use of bevacizumab in older patients with metastatic breast, lung, or colon cancer. They found that bevacizumab (Avastin) was contraindicated in approximately one-third of patients in whom it was used.
Study Details
In the study, the SEER-Medicare database was used to identify bevacizumab use in patients older than 65 years with metastatic breast, lung, and colon cancer who were diagnosed between 2004 and 2007 and followed to 2009. Contraindication to bevacizumab use was defined as having at least two billing claims before bevacizumab treatment for thrombosis, cardiac disease, stroke, hemorrhage, hemoptysis, or gastrointestinal perforation. Toxicity was defined as the first development of one of these conditions after bevacizumab therapy.
Among 16,085 patients identified, 3,039 (18.9%) had received bevacizumab. In a multivariate analysis, black race (odds ratio [OR] = 0.81, P = .03) and Hispanic ethnicity (OR = 0.65, P = .04) were associated with decreased receipt of bevacizumab compared with white race. Receipt of bevacizumab was also significantly associated with later year of diagnosis, tumor type, and decreased comorbid conditions.
Contraindicated Use
Of patients who received bevacizumab, 1,082 (35.5%) had a contraindication, including cardiac disease in 19%, hemorrhage in 15.7%, and thrombosis in 13%. An additional 1,315 patients (43.0%) had a history of a caution. In multivariate analysis, receipt of bevacizumab with a contraindication was associated with black race (odds ratio [OR] = 2.6, P = .003), increased age, comorbidity, earlier year of diagnosis, and lower socioeconomic status. The odds ratio for patients in the highest socioeconomic status quintile was 0.63 (P = .03) compared with patients in the lowest quintile. Patients with lung (OR = 1.7, P = .01) and colon cancer (OR = 1.4, P = .03) were more likely to have a contraindication.
Complications in Indicated Use
In the group with no contraindication, 30% had a complication after starting bevacizumab, including thrombotic complications in 12.1%, hemorrhagic complications in 11.9%, and cardiac complications in 10.6%. Cardiac and hemorrhagic complications were more common in patients with lung cancer, and thrombotic complications were more common in patients with colon cancer. On multivariate analysis, black patients were more likely to have a complication compared with white patients (OR = 1.9, P = .007). Risk of complications was significantly reduced in unmarried patients and significantly increased in patients with higher comorbidity scores and in patients with colon cancer vs breast cancer.
The investigators concluded: “Our study demonstrates widespread use of bevacizumab among patients who had contraindications. Black patients were less likely to receive the drug, but those who did were more likely to have a contraindication. Efforts to understand toxicity and efficacy in populations excluded from clinical trials are needed.”
The study was supported by the National Cancer Institute.
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