Dr. Jochen H. Lorch, Assistant Professor of Medicine at Harvard Medical School and Director of the Thyroid Cancer Center at the Dana-Farber Cancer Institute, notes that though some patients with medullary thyroid cancer (MTC) can live with their disease without progression for long periods of time, the majority will eventually enter a phase in which their cancer becomes more aggressive. The unique feature about the biology of MTC is that there are often extended periods without any progression at all, or only a gradual progression. During that stage, surveillance with sequential calcitonin, CEA and calcium measurements, sequential imaging, such as thyroid or neck ultrasounds, CT scans and bone scans, are necessary to catch the moment when the disease is turning more aggressive, at which point systemic treatment should then be considered.
Currently, there are two FDA approved treatments for patients with MTC after progression, beyond the initial treatment of surgery and surveillance. The drugs include Vandetanib (Caprelsa) and Cabozantinib (Cometriq), however they are not well tolerated in most cases and neither provides a cure.
Dr. Lorch discusses, “The other group of trials that will be coming are RET inhibitors. In many ways, they are similar to Vandetanib and Cabozantinib, but they more specifically block the RET proto-oncogene that’s driving MTC in the majority of cases.” The hope is that this will add another treatment option for MTC because none of the FDA-approved treatments are curative. Dr. Lorch notes, “Eventually, these patients progress and it’d be good to have another line of treatment available.” Another hope Dr. Lorch discusses is that these drugs might be a little more favorable in terms of toxicity. The two approved drugs have rather significant toxicities, but new drugs may be better tolerated because they may be more specific to the actual target that is driving the cancer. However, Dr. Lorch states,“While we know that RET is driving those cancers, it’s not entirely clear whether these other 2 drugs act through inhibition of RET or if there’s other targets, such as VEGF, that also contribute to responses, so the hope is that they’ll be equally efficacious with less toxicity. But this will need to be tested and that will be the work of the next couple of years.”
The Thyroid Cancer Care Collaborative (TCCC) aims to provide the more comprehensive treatment to patients over the course of their lifetime. This includes notifying patients of current and new treatments, such as future possible treatment options for MTC, in order to ensure that all patients are receiving the highest level of care and achieving the best possible outcome.