Metastatic Colorectal Cancer Therapy Not Reaching All Patients

In a nationwide study, less than a quarter of colorectal cancer patients eligible to use the drug bevacizumab (Avastin) actually received it as first-line therapy in the year after it was approved by the Food and Drug Administration, according to a new study led by Duke Comprehensive Cancer Center and Durham Veterans Affairs Medical Center researchers.

"Since it was FDA-approved, bevacizumab, in combination with chemotherapy, is the first-line standard of care for most patients with metastatic colorectal cancer," said Yousuf Zafar, M.D., an oncology fellow at Duke and lead investigator on this study. "It's interesting to know that so few patients received this first-line treatment in the first year after approval."

Bevacizumab is a member of a class of drugs known as antiangiogenics; it works by choking off a tumor's blood supply. It was FDA-approved in 2004 to treat colorectal cancer that has spread to other organs.

The researchers found that patients with non-private insurance had significantly lower odds -- 66 percent lower -- of receiving bevacizumab than those with private insurance. Women and those with co-morbidities -- other serious medical conditions -- were significantly more likely to receive the treatment.

"Bevacizumab has significantly increased the cost of colorectal cancer care," Zafar said. An eight-week course of bevacizumab can cost over $9000. "So it's not surprising that those with private insurance were more likely to receive the drug than those without insurance, or those with non-private insurance. This is a cause for concern, especially as all patients should have access to effective new agents."

Zafar said more patients are receiving the drug now, but the study results showed that at the time of approval, insurance type was associated with being treated with the drug.

The researchers will share their findings in a poster presentation at the annual American Society of Clinical Oncology meeting in Chicago, on June 1, 2008. The study was funded by the National Cancer Institute and the Department of Veterans Affairs.

Zafar and his colleagues reviewed treatment data for almost 400 colorectal cancer patients treated after bevacizumab was approved. The patients were treated in multiple health systems, including Veterans Affairs hospitals, private oncology practices, managed care settings, and academic medical centers.

"We found that overall, 22 percent of the patients we studied received bevacizumab as a first treatment for metastatic colorectal cancer," Zafar said.

Zafar could only speculate why women might be more likely than men to receive the first-line therapy.

"Other research has shown that women tend to ask more questions, do more research and be more proactive about their health, so this could've played a role," he said.

The researchers had hypothesized that patients with co-morbidities would be less likely to receive bevacizumab as a first-line therapy, so finding the opposite was a surprise.

"All of these findings are important first steps in working to ensure that patients receive the very best treatment possible for their cancers," Zafar said. "These data will be important as we work to understand who gets treated with newer anti-cancer agents and how to make cancer treatment more equitable."