Important research into thyroid cancer is being done right now in many university hospitals, medical centers, and other institutions around the country. Each year, scientists find out more about what causes the disease, how to prevent it, and how to improve treatment. In past years, for example, evidence has grown showing the benefits of combining surgery with radioactive iodine therapy and thyroid hormone therapy. The results include higher cure rates, lower recurrence rates, and longer survival.
Genetics
The discovery of the genetic causes of familial (inherited) medullary thyroid cancer now makes it possible to identify family members carrying the abnormal RET gene and to remove the thyroid to prevent cancer from developing there.
Researchers are optimistic that progress in understanding the abnormal genes that cause sporadic (not inherited) thyroid cancer, especially papillary cancer, will eventually lead to better treatments.
Treatment
New treatments for thyroid cancer are being tested in clinical trials.
Radioactive iodine (RAI) therapy
Research continues to see which patients are likely to have their cancers come back after surgery. These patients may be helped by getting RAI therapy after surgery. Recent studies have shown that patients with very low thyroglobulin levels 3 months after surgery have a very low risk of recurrence even without RAI. More research in this area is still needed.
Chemotherapy
Some studies are testing the value of chemotherapy drugs such as paclitaxel (Taxol®) and other drugs, as well as combined chemotherapy and radiation in treating anaplastic thyroid cancer.
Targeted therapies
In general, thyroid cancers do not respond well to chemotherapy. But exciting data are emerging about some newer targeted drugs. Unlike standard chemotherapy drugs, which work by attacking rapidly growing cells in general (including cancer cells), these drugs attack specific targets on cancer cells. The targets they attack can be present on normal cells as well, but the goal is to find targets that help cancer cells grow and survive.
Tyrosine kinase inhibitors: A class of targeted drugs known as tyrosine kinase inhibitors (TKIs) may help treat thyroid cancer cells with mutations in certain genes, such as BRAF and RET/PTC. Many of these drugs also have anti-angiogenic properties (see below).
Tyrosine kinase inhibitors that have shown promise against thyroid cancer in clinical trials include sorafenib (Nexavar®), sunitinib (Sutent®), pazopanib (Votrient®), cabozantinib (XL184), motesanib (AMG 706), axitinib (AG-013736), and vandetanib.
Vandetanib is the first drug shown to be helpful in the treatment of medullary thyroid cancer (MTC) in a large clinical trial, and is now approved for use against advanced forms of the disease. Some other TKIs, such as sunitinib and sorafenib, are already approved to treat other types of cancer, and may be useful against MTC and differentiated thyroid cancers if other treatments are no longer working.
Cabozantinib (XL184), a drug that attacks RET and several other targets, is another promising new drug for MTC. It has been found to shrink or slow the growth of a large percentage of advanced tumors in early studies.
Anti-angiogenesis drugs: As tumors grow, they need a larger blood supply to get enough nutrients. They get it by causing new blood vessels to form (a process called angiogenesis). Anti-angiogenesis drugs work by disrupting these new blood vessels. Some of the tyrosine kinase inhibitors listed above, such as sunitinib, sorafenib, pazopanib, and cabozantinib, have anti-angiogenic properties.
Another drug with these properties is combretastatin A-4 phosphate (CA4P), which has shown some promising early results and is now being tested in larger studies. Lenalidomide, a drug with anti-angiogenic effects used in some blood cancers, has also shown some promising results in a recent, small study.
Feedback
