Impact of BRAF, TERT, and novel mutations on the efficacy of lenvatinib for advanced papillary thyroid cancer: A national genomic database analysis

Why this matters for people with thyroid cancer

Most people with thyroid cancer do very well after surgery and standard treatments. But for some, the disease comes back or spreads and no longer responds to radioactive iodine, leaving far fewer options. This study asks a question that matters directly to those patients and their families: do specific DNA changes in the tumor help predict how long a key drug, lenvatinib, will keep the cancer under control—and can these clues eventually guide more personalized treatment?

A closer look at a hard-to-treat group

Researchers in Japan used a nationwide cancer genomics database to study 165 people with advanced papillary thyroid cancer, the most common type of thyroid cancer. All of them had disease that no longer responded to radioactive iodine and were treated with lenvatinib as their first drug treatment. Alongside routine clinical information such as age, sex, and where the cancer had spread, the team had detailed genetic profiles of each person’s tumor, generated by approved genomic tests used across the country. This allowed them to connect the dots between the tumor’s DNA and how long lenvatinib remained effective.

Key gene changes under the microscope

The investigators focused first on two well-known genetic changes in papillary thyroid cancer: mutations in a gene called BRAF and changes in the promoter region of a gene called TERT, which helps control chromosome ends. In earlier, surgery-based studies, these alterations have been linked to more aggressive disease and worse survival. Surprisingly, in this group of patients already living with advanced cancer, the pattern looked different. Tumors with BRAF mutations actually stayed controlled on lenvatinib for longer than those without, while TERT changes—either alone or combined with BRAF—did not shorten the time before lenvatinib stopped working.

New warning flags for early treatment failure

The team then scanned dozens of other genes that were commonly altered in these tumors. They found that mutations in five genes—KMT2A, MTOR, MUTYH, CREBBP, and RICTOR—were each linked to a two- to almost threefold higher risk that lenvatinib treatment would fail sooner. These genes are involved in how cancer cells repair DNA damage, adjust their metabolism, and switch groups of other genes on or off. In follow-up checks, the researchers confirmed that patients with any mutation in this five-gene set consistently had shorter benefit from lenvatinib, even when the dataset was split into separate training and test groups. However, because many of the specific mutations were rare and not all have proven biological effects, the authors emphasize that these signals are exploratory and need to be validated in future studies.

What the findings do—and do not—mean

Importantly, common clinical features such as age, sex, smoking history, and which organs were affected did not meaningfully predict how long lenvatinib worked. That suggests the tumor’s molecular makeup may matter more than traditional risk factors once the disease is advanced. At the same time, the study has real-world limitations. In Japan, comprehensive genomic testing is usually done late in the course of illness, and only in patients well enough to undergo it, so the group may be biased toward people who have already lived longer with their cancer. The authors also had to use “time to treatment failure”—when lenvatinib was stopped for any reason—rather than the stricter imaging-based measures used in clinical trials, and genetic testing platforms differed somewhat in which regions they covered.

What this could mean for future care

For patients and clinicians facing difficult decisions about advanced papillary thyroid cancer, this study offers both reassurance and new directions. It suggests that lenvatinib remains a strong first-line option even when tumors carry BRAF and TERT changes that are usually considered bad news, and that these mutations alone should not discourage use of the drug. At the same time, the discovery of a small set of other gene changes linked to earlier failure hints at the possibility of more refined risk tools in the future—and even combination strategies that pair lenvatinib with drugs targeting DNA repair, metabolism, or gene-control pathways. While these ideas are not ready for routine practice, they point toward a future in which the genetic fingerprint of each person’s tumor could help tailor both the choice and timing of therapies.

Citation: Sato, Y., Fukuda, N., Yamamura, K. et al. Impact of BRAF, TERT, and novel mutations on the efficacy of lenvatinib for advanced papillary thyroid cancer: A national genomic database analysis. npj Precis. Onc. 10, 176 (2026). https://doi.org/10.1038/s41698-026-01371-8

Keywords: papillary thyroid cancer, lenvatinib, tumor genetics, targeted therapy, treatment resistance