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• Posted October 28, 2024

New Hope Against a Rare, Aggressive Form of Thyroid Cancer

Most thyroid cancers are slow-moving and, if caught early, curable.

But some patients can present with what's known as an anaplastic thyroid carcinoma (ATC) -- a rare and very aggressive tumor with a very poor prognosis. 

Now, a clinical trial offers new hope to patients with a certain subtype of this tumor.

Combining cancer immunotherapy with another treatment -- targeted to a particular genetic mutation found on some ATC tumor cells -- appears to extend patient survival, doctors in Texas report.

“Patients with anaplastic thyroid carcinoma need treatments that work fast, and we saw promising results with this combination treatment approach," said lead investigator Dr. Maria Cabanillas. She's a professor of endocrine neoplasia and hormonal disorders at the University of Texas' MD Anderson Cancer Center in Houston.

Her team published its findings Oct. 24 in the journal JAMA Oncology.

As the researchers explained in a hospital news release, ATC tumors can differ genetically patient to patient, and "each subtype has distinct driver mutations that can influence tumor behavior and progression."

About 40% of ATC tumors have mutations in the BRAF gene that help drive the cancers' behavior and prognosis. The new trial focused on 42 patients battling a BRAF-mutated ATC.

Eighteen of the patients received three drugs: Atezolizumab (Tecentriq), a monoclonal antibody immunotherapy drug, plus a combination of vemurafenib and cobimetinib, two drugs targeted to the BRAF mutation.

The median overall survival of patients in that group was just over 43 months, with about half of patients responding favorably to the regimen, the Houston team said.

A second group of ATC patients included 21 people battling tumors with mutation known as RAS (NRAS, KRAS or HRAS), or patients with NF1/2 mutations. This group got a combination of atezolizumab plus cobimetinib, but overall median survival was much shorter, just 8.7 months. Only 14% of patients responded to that therapy, the team said.

Finally, three other ATC patients with none of the tumor cell mutations detected in the prior two groups received atezolizumab plus bevacizumab (Avastin). Their median over survival was just over 6 months, with only a third or patients responding.

The new trial shows how important pinpointing specific ATC mutations can be in determining a treatment course that might extend survival.

"The takeaway from this study is that immunotherapy really does add benefit for patients," Cabanillas said in a university news release. But she added that more research is needed into devising effective treatments for patients with ATC whose tumors carry non-BRAF mutations.

“There are no approved and effective therapies for ATC with non-BRAF mutations, and we continue to focus our research in that area,” she said. “We are working to optimize outcomes for our patients. We want them to live longer and better lives, and this study offers hope for patients with ATC.” 

More information

Find out more about anaplastic thyroid carcinoma at the Cleveland Clinic.

SOURCE: University of Texas MD Anderson Cancer Center, news release, Oct. 24, 2024