Medullary thyroid cancer
Medullary thyroid cancer is found in 3% of all thyroid cancers, and it is mostly in women than in men. At an early stage, it accidentally is revealed by the patient himself or at checkup. It can have a sporadic nature as a result of negative impact (not associated with radiation exposure) between the ages of 40 and 60 and it is about 80% of medullary cancer cases. Patients with inherited RET oncogene mutation are in the remaining 20%.
This cancer type develops from parafollicular C cells, which produce a substance called calcitonin, and have no relation to the thyroid hormone.
Heredity in medullary thyroid cancer
As a result of RET mutation, a precancerous condition occurs in the thyroid cells called cellular hyperplasia, in which cells begin to divide out-of-control.
Inherited usual form of medullary cancer occurs between the ages of 40-50 years and it is the least aggressive form of all thyroid cancers.
MEN II-A or Sipple syndrome is inherited by descendants in 50% of cases. It includes various endocrine disorders and may be in the form of bilateral medullary carcinoma, pheochromocytoma and hyperparathyroidism. It оccurs after 30 years old age.
MEN II-B. Inheritance is also dominant, and it is equally expressed with the same rate in both men and women. The disease occurs after 30 years old age. It includes medullary cancer, pheochromocytoma and rarely hyperparathyroidism, as well as the Marfanoid habitus syndrome. Pheochromocytoma is removed prior to surgery on the thyroid gland, because there may be the risk of complications due to hypertension.
For medullary cancer you should pay attention to the following symptoms:
- Neck contour change.
- Palpable neoplasm as a node or lump.
- Enlarged neck lymph nodes.
- Voice change.
- Pain syndrome. Although medullary thyroid cancer usually does not cause any pain, but sometimes the pain manifests itself during palpation, spreading with local metastasis to the deeper thyroid tissues or lymph nodes.
- Diarrhea. During growth abnormal cells of the medullary cancer produce a lot of protein, calcitonin and other substances, which is a sign of tumor progression.
Diagnosis of medullary cancer
Physical examination by a doctor
Doctors perform physical examination. In this way they identify suspicious nodes and tumors on the patient neck. The majority of newly diagnosed thyroid tumors are determined during a routine checkup by a doctor, or after undergoing an neck ultrasound or radiography for other reasons. Usually tumors have the form of lump or nodule. It may have a visible contour or sticking out in the side or front of the thyroid gland. For more accurate information the doctor refers a patient to a neck ultrasound.
Instrumental and laboratory diagnosis
Ultrasound images provide accurate information about the thyroid gland and determine the progression of medullary cancer. An ultrasound examines the condition of the thyroid gland, central and lateral lymph nodes around the neck. If a malignancy is suspected, a fine-needle biopsy is performed, which can be used to make an adequate diagnosis. Also it need to carry out genetic testing and screening for the presence of certain mutations.
In cases of suspected medullary thyroid cancer, it is also recommended to perform:
- Ultrasound of the abdominal and retroperitoneal space.
- CT chest and abdomen.
- Urine analysis for methylated catecholamine derivatives (metanephrine, nortenifrin).
- Blood test for serum calcitonin levels and cancer-embryonic antigen.
- Examination of the endocrine system for the pheochromocytoma and hyperparathyroidism.
Treatment of medullary thyroid cancer in Israel
Аfter getting the results of a fine-needle biopsy and confirmation of suspicions concerning the medullary carcinoma, it is recommended to perform immediately a surgical procedure. Surgery depends on the tumor size and the metastatic lesion.
In the case of a medullary thyroid cancer, for any size of the primary tumor, a minimal volume of operation is recommended – thyroidectomy with central lymphadenectomy, in which all lymph nodes and fatty tissues in the central neck area are removed. Additional lymph nodes of the neck are removed only with cytological confirmation using a fine-needle biopsy.
With a more aggressive form of medullary cancer, when the cancer has spread beyond the thyroid gland into nearby tissues, such as the trachea, the nerves of the vocal cords or the esophagus, the surgeon needs to modify the operation to completely remove the cancer.
If 2-3 months have passed after the surgery and an increase in the level of serum calcitonin or cancer-fetal antigen is detected, PET / CT chest and abdominal organs is performed to prevent tumor recurrence.
Radioactive iodine treatment of medullary thyroid cancer
Since parafollicular C cells, unlike other thyroid cells, do not absorb iodine, the treatment with radioactive iodine does not have any effect and does not allow to detect abnormal cancer cells with PET-CT using iodine.
Personalized treatment of medullary thyroid cancer
In case of non-operated locally advanced tumor or the presence of distant metastases, as well as proven tumor progression, personalized genetic oncotests can be performed. Doctor and patient receive a detailed report about FDA-approved innovative and promising biological therapies. It allows to select more targeted and effective treatment for medullary thyroid cancer.
Prevention and surveillance
In order to prevent medullary thyroid cancer in patients with RET mutation, it is recommended to perform a preventive thyroidectomy. Age for the preventive surgery depends on the mutation type of RET gene.
Analyzes and diagnosis are carried out:
- For calcitonin, CEA, neck ultrasound – once every six months.
- CT scan of the chest – once a year.
If level of serum calcitonin is:
- less than 10 ng / ml – additional examination is not carried out;
- more than 150 ng / ml (or CEA) – additional examination, such as PET / CT, MRI is recommended.
Survival in medullary thyroid cancer
Unlike the differentiated type of thyroid cancer – papillary and follicular, the cure rate of medullary cancer is lower and the 10-year survival rate is:
- The tumor is limited to the thyroid gland – 90%,
- Within the neck lymph nodes – 70%,
- With distant metastases – 20%.