Can Molecular Analysis be Tapped to Tackle Brain Cancer?

Compared to treatment advances for other types of cancer, progress in treating brain cancer has been frustratingly slow. Still, understanding the molecular changes that drive brain cancer remains “potentially transformative,” says Paul Mischel, a cancer biologist and neuropathologist at the Ludwig Institute for Cancer Research in San Diego.

In the Winter 2017-2018 issue of Cancer Today, science writer Stephen Ornes explores the hopes and challenges of using molecular analysis in diagnosing and treating brain tumors. Right now, molecular biomarkers can help predict a brain tumor’s likely response to the chemotherapy drug Temodar. This testing can also help assess the risk that a tumor will grow and spread and can reveal certain genetic variants in the tumor that may respond to experimental treatments. However, genomic testing of brain tumors has yet to uncover ways to extend survival beyond that provided by standard treatments.

Neurons in the brain. Image © iStock / yodiyim; 123RF / Rostislav Zatonskiy.

On one hand, patients who undergo genomic testing may learn they qualify for a clinical trial to test a new treatment specific to a genetic alteration in their tumor. On the other hand, patients may discover that genomic testing reveals no actionable information. Michael Yutkin, an asset manager in Irvine, California, who was diagnosed with glioblastoma in August 2012, had his tumor tissue analyzed in the spring of 2016. Five of the six genomic alterations the test found weren’t associated with recommended treatments or clinical trials. The sixth alteration, an amplification of the EGFR gene, has responded to tyrosine kinase inhibitors in patients with other cancer types. However, most glioblastoma patients with an EGFR amplification have not responded to these drugs in clinical trials, so it wasn’t a treatment option for Yutkin.

“I’m not sure how much it really told us,” Yutkin says, though he doesn’t regret getting genomic analysis to learn more about his tumor. Yutkin is hoping to enroll in a clinical trial for an experimental cancer vaccine or another immunotherapy. “The field isn’t moving fast enough,” he says.

Molecular analysis is not yet the universal standard of care for patients with brain cancer, says David Arons, CEO of the National Brain Tumor Society and chair of the National Cancer Institute’s Council of Research Advocates, although he predicts it will be in the next few years. Because these tests haven’t been associated with a clear patient benefit in all cases, they’re not universally covered by Medicare, and “there is resistance from insurance companies” to reimburse for them, says Emil Lou, a medical oncologist at Masonic Cancer Center at the University of Minnesota in Minneapolis.

This makes for a frustrating Catch-22, the article explains: Information derived from molecular testing hasn’t been shown to improve survival, but researchers won’t be able to explore new treatments without more tumors being tested. In other tumor types—like lung and breast cancers—genomic testing has already influenced the development of new drugs and guided oncologists to use targeted therapies for patients whose tumors have specific mutations.

This story was excerpted from Cancer Today, a magazine for cancer patients, survivors and caregivers published by the American Association for Cancer Research. Read the full article to learn more about the challenges of genomic testing in brain cancer and find more stories from patients who have used genomic analysis.

 

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