Thyroid Cancer - Overview

Thyroid cancer was first described at the end of the eighteenth century. For one and a half centuries surgery remained the only effective therapeutic option for this cancer, until in 1946 radioiodine therapy was performed for the first time. Radioiodine therapy was brought to Germany 4 years later, in 1950. In the intervening 50 years, the use of iodine-131 has proved able to cure the cancer and its metastases. Percutaneous radiation therapy had been added to the therapeutic armamentarium, but even now there is heated debate as to its potential.

Suppressive L-thyroxine supplement is a prerequisite for successful treatment, while cytotoxic drugs are mainly used for palliation.

During the past 10 years, various new diagnostic and therapeutic approaches have been introduced. High-dose radioiodine therapy as well as redifferentiation therapy with retinoic acid seem beneficial.

Diagnostic procedures such as magnetic resonance imaging (MRI), positron emission tomography (PET), as well as isonitriles (MIBI) and thallium (²⁰¹ Tl), have proved useful for the follow-up of thyroid cancer.

Two special issues are also discussed in this book. Iodine supplementation in areas of iodine deficiency has led to a change in pathology insofar as papillary thyroid cancer (with a better prognosis) has become more frequent than follicular carcinoma. A special chapter is dedicated to thyroid cancer in Chernobyl children.

The thyroid gland is located low in the front of the neck, below the Adam's apple. The gland is shaped like a butterfly and wraps around the windpipe or trachea. The two wings or lobes on either side of the windpipe are joined together by a bridge, called the isthmus, which crosses over the front of the windpipe.

Thyroid cancer accounts for nearly 2% of all new cancers diagnosed in the United States every year, according to the U.S. Surveillance, Epidemiology, and End Results cancer registry (SEER) predictions. Over the last 10 years, thyroid cancer has had a larger increase in incidence than any other type of cancer.

Thyroid cancer occurs in all age groups, although its incidence increases with age, especially after 30 years of age. More aggressive forms of thyroid cancer are found in older patients. Thyroid cancer occurs three times more frequently in women than in men. Thyroid cancer originates from one of two different types of thyroid cells: follicular cells or so-called parafollicular, or C cells.

Medullary thyroid cancer remains a challenge for interdisciplinary diagnosis and therapy. The fate of the patient with medullary thyroid cancer is determined by surgery. Removal of all accessible lymph nodes and their metastases is mandatory. Percutaneous radiation therapy is usually not successful. The same holds true for cytotoxic medication. Nuclear medicine now provides new imaging procedures such as those taking advantage of In-octreotide and I-metaiodobenzylguanidine (mIBG) as well as Tc-dimercaptosuccinic acid (DMSA). mIBG and octreotide analogues may have therapeutic potential but have not yet been evaluated clinically in sufficiently large groups of patients.