Endocrine and thyroid tumours
EPIDEMIOLOGY
Thyroid cancer is rare, with an annual incidence of between 2.2 and 3.5 per 1,000 in the United States. It has tended to increase in frequency in recent years, probably because of improvements in diagnostic methods, which have allowed tumours previously missed to be detected.
Thyroid cancer is commoner in women. It can be triggered by accidental exposure to ionising radiation and by genetic factors.
The diagnostic procedure for thyroid cancer is not an easy one, and an operation is not decided upon until after reflection between all specialists concerned: endocrinologists, radiologists, nuclear specialists, pathologists and surgeons. This multidisciplinary approach allows the most suitable treatment to be decided upon for each case discussed.
Cancer of the thyroid develops slowly and carries a favourable prognosis. There is however a risk of recurrence, mainly within 5-10 years, and regular monitoring will therefore be necessary.
SYMPTOMS
Thyroid cancer is sometimes visible or palpable: it causes a slight swelling, like a “ball”, at the base of the neck. Although it can cause hoarseness or problems with swallowing, it is often discovered quite by chance, during an X-ray examination of the neck in connection with something else.
DIAGNOSTIC
Diagnosis is based on imaging techniques and on fine-needle nodule puncture.A thyroid ultrasound will provide important information on “nodules”, which are small tumours that develop in the thyroid but are not necessarily cancer. The ultrasound is therefore combined with a puncture of the nodule, using a fine needle, and a microscope analysis of cells obtained from the puncture.
These examinations must be conducted very carefully in order to guarantee their reliability.
In some cases, a scintigraph is conducted in addition to the examination. This involves intravenous injection of a very small amount of radioactive substance, which the thyroid captures. An instrument placed close to the neck detects radiation given off by the product. Scintigraphy can help better define the characteristics of nodules. The information provided in these various examinations dictates the treatment chosen.
Difficulties encountered in diagnosis and treatment of thyroid cancer have led the European scientific community to put together a series of recommendations. The specialists in the thyroid cancer multidisciplinary group have played an active role in compiling these consensus texts. They have also conducted considerable research into factors that influence the development of thyroid cancer. Identification of these markets helps refine the treatment further.
Thyroid ultrasound, nodule puncture, microscope examination of puncture samples and scintigraphy are the principal diagnostic examinations for cancer of the thyroid.
Cancer thyroïdien papillaire
TREATMENT
The prognosis for thyroid cancer is generally good. Effective treatment depends first of all on an efficient surgical approach. Thyroid surgery, which involves complete removal of the gland (thyroidectomy), is difficult because of the proximity of the vocal cords and parathyroid glands. The parathyroid glands are small, very close to the thyroid, and help regulate calcium and phosphorus in the blood. The surgeon’s skill will help overcome the potential risks of this operation.
Administration of radioactive iodine sometimes follows the operation. Iodine is essential for synthesis of thyroid hormones, and radioactive iodine destroys the few cancer cells in the thyroid that might have escaped the surgery.
Additional treatment with radioactive iodine requires radioactivity protection measures to protect the immediate and more distant environment. The patient must kept for two to three days in a shielded isolation room.
Surgery and radioactive iodine will generally cure the cancer. Surveillance, essential because of a risk of recurrence, is straightforward and involves a test that is very reliable if conducted properly. In this case, levels of thyroglobulin in the blood must be measured.
Thyroglobulin, produced specifically by the cells in the thyroid gland, is the storage protein for thyroid hormones.
After removal of the thyroid, thyroid hormone replacement treatment must be given.
Numerous international studies are concentrating on treatment of thyroid cancer. Participation in these studies has provided patients at the Cancer Centre with treatment based on the most recent progress.
Numerous international studies are concentrating on treatment of thyroid cancer. Participation in these studies has provided patients at the Cancer Centre with treatment based on the most recent progress.
