Important research into thyroid cancer is under way 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.
Recent identification of the genetic causes of familial (inherited) medullary thyroid cancer now makes it possible to identify family members carrying the abnormal gene and to prevent cancer from developing. 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.
New treatments for thyroid cancer are being tested in several types of clinical trials.
Research to better define who needs RAI therapy after surgery is ongoing. A promising approach was described in a presentation recently using blood tests for thyroglobulin after thyroid surgery. If the thyroglobulin was very low after 3 months, RAI was not given to some of these patients and after 3.2 years none of them have had a recurrence. However, these results are preliminary and more research is needed.
Some studies are testing the value of newer chemotherapy drugs such as paclitaxel (Taxol) and other drugs, as well as combined chemotherapy and radiation in treating anaplastic thyroid cancer.
In general, thyroid cancers have not been found to 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 (which includes 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 has already been used successfully in some other forms of cancer. These drugs may help reverse the abnormal growth of thyroid cancer cells that results from mutations of certain genes, such as BRAFand RET/PTC. Many of them also have anti-angiogenic properties (see below) Some of the tyrosine kinase inhibitors being tested against thyroid cancer in clinical trials include sorafenib (Nexavar), sunitinib (Sutent), motesanib (AMG 706), axitinib (AG-013736), and vandetanib (Zactima). Several studies have been recently reported showing that these drugs can shrink many thyroid cancers. None will likely be a cure, but will cause some shrinkage in many thyroid cancers. These studies are promising, but they are not yet routine treatments for thyroid cancer. Studies combining these agents with other agents like chemotherapy will be done to try to increase the benefits.
Anti-angiogenesis drugs: As tumors grow, they need a larger blood supply to get enough nutrients. They do this 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 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 shown some promising results in a recent, small study.
Monoclonal antibodies: Monoclonal antibodies are man-made versions of immune system proteins designed to attack a very specific target. Studies are testing radiolabeled monoclonal antibodies (antibodies with radioactive material attached) for treating medullary thyroid cancer (MTC). The antibodies help deliver the radiation to the cancer cell. Carcinoembryonic antigen (CEA) is a protein that is not normally found in adult tissues. But many MTCs make CEA. Since radioiodine treatment is not useful in MTC because MTC does not take up iodine, the ability to deliver radiation (and other treatments) to MTC cells by bonding radioactive material to anti-CEA antibodies appears promising. Studies of this technique are in progress.
Last Medical Review: 04/28/2009
Last Revised: 05/14/2009