A 71-Year-Old Woman with NTRK Gene Fusion Thyroid Cancer - Episode 2
Jochen H. Lorch, MD, MS: This is a little bit of an odd case. To have a presentation with a thyroid nodule that’s palpable is very typical, and for this to be papillary thyroid cancer is also completely unremarkable. That is frequently the case. Where this case is a little bit unusual is that, first, the papillary thyroid cancer, which was 3.8 cm in diameter, had already metastasized to several lymph nodes in the central neck compartment. That can happen. But the brain metastases were definitely unusual. We only see brain metastases in about 15% of all patients with papillary thyroid cancer or with iodine-refractory thyroid cancer, which is not necessarily what this patient has. So this is definitely an unusually aggressive thyroid cancer.
Having brain metastases obviously raises the stakes of treatment in this considerably, since the prognosis for cancer in general that has spread to the brain is generally much less favorable than without brain metastases. The classical treatment for this would be evaluation by neurosurgery. It sounds like there were multiple brain lesions, so it’s likely not a case that would be amenable to resection of these multiple nodules. But whole brain radiation or stereotactic radiation to these individual brain lesions is also something that could classically be considered.
Now, this tumor being NTRK fusion positive obviously gives us another option to treat with larotrectinib or a similar drug, which is entrectinib, and has a very similar profile. The incidence of NTRK fusion positive thyroid cancer is relatively high compared to other types of cancers. Across the board of all cancer types, the incidence is roughly 1%. But with thyroid cancer, it’s in the order of 10% to 15%. There also seem to be some geographical variations; for example, in Japan, the incidence seems to be a little bit higher. There’s also a higher incidence of fusion NTRK3, which is related to radiation exposure and has been described in people who were exposed to radioactive iodine and radiation during the Chernobyl disaster in Ukraine.
Transcript edited for clarity.
Case: A 71-Year-Old Woman With Thyroid NTRK Gene Fusion Cancer
Clinical Workup and Initial Treatment
Follow-Up and Additional Treatment