There are three main types of treatment for thyroid cancer: surgery, radioactive iodine, hormone therapy. Discover the essentials of the management of thyroid cancer with Prof. Jean-Louis Peix from the endocrine surgery department of the Center Hospitalier de Lyon Sud.
In this article, we will limit ourselves to the treatment of differentiated cancers of the thyroid, which represent more than 80% of cases.
Surgical treatment should eradicate the thyroid tumor and prevent the cancer from spreading to other areas of the body with the help of thyroid surgical instrument set. Currently, there is a consensus that removing the entire thyroid gland (total thyroidectomy) is the best treatment. During the operation, the examination of the extracted tissue (called extemporaneous anatomo-pathological examination) can confirm the diagnosis of cancer.
For practical and technical reasons, some diagnoses (20%) are deferred, that is to say they are impossible to obtain during the operation. But when the diagnosis of cancer is stopped by the extemporaneous examination, the risk of error (false positive for cancer) is almost zero (less than 1%).
To control a possible spread of cancer to surrounding areas, this surgical procedure can be accompanied by ablation of the ganglion chains located around the thyroid and along the trachea. These chains are the preferred pathways for tumor cell propagation. This surgical procedure called dissection depends on the stage of the disease: it is particularly indicated if the surrounding lymph nodes are swollen and visibly invaded by tumor cells.
In cases of very localized cancers of less than one centimeter (micro-cancer), some teams do not perform such a dissection. This does not seem to increase the risk of recurrence. But the current trend is to resort to it more and more systematically “says Prof. Peix.
How long does the operation take? “In trained hands, surgery for thyroid cancer can be considered benign with a hospital stay that does not exceed 2 or 3 days after the operation” specifies Prof. Peix. And complications from surgery are infrequent.
Present in 1 to 10% of cases, the main one is the risk of transient paralysis of a vocal cord (responsible for a hoarse voice). This side effect can sometimes require speech therapy. But the risk of this problem persisting is very low (0.5 to 2%);
The second risk is postoperative hypocalcemia (calcium deficiency) linked to dysfunction or ablation of the parathyroid glands responsible for regulating the levels of this trace element. Frequent in the weeks following the operation (10 to 50% of patients), it is the most transient. In the event of persistence (very low risk of 1 to 5%), lifelong treatment will be necessary;
The scar, much feared by patients, is extremely discreet if not zero. “A few months after the operation, when the incision has been made in satisfactory conditions (horizontal incision), the cosmetic results are considered very satisfactory by more than 90% of patients” specifies Prof. Jean Louis Peix.
After the operation, improve the quality of life
After the operation, the patient receives additional treatment with radioactive iodine (iodine 131), except in cases of very low risk of relapse. This treatment, also called metabolic radiotherapy, is based on the particular affinity of the thyroid cells for this radioactive element. By attaching itself to them, iodine 131 will destroy the remaining thyroid tissue.
This treatment requires, for radiation protection reasons, hospitalization of 3 to 5 days. “Until recently, this treatment only intervened after a month of prolonged withdrawal from treatment with thyroid hormone. This led to hypothyroidism and therefore a significant deterioration in the quality of life. Recently, one can use a new drug just after the operation (recombinant human TSH or rhTSH), which prevents any hypothyroidism and reduces the length of time off work by more than 10 days, explains Prof Peix.
To compensate for the absence of a thyroid, the operated patient will be prescribed thyroxine (a thyroid hormone) to be taken on an empty stomach every morning. This product also helps to keep the level of TSH (pituitary thyroid stimulating hormone) as low as possible, which avoids stimulating the growth of possible cancer cells. The thyroxine dosage can be adjusted according to the blood dosages.
Follow-up after treatment
Every six months to a year, the patient will benefit from regular follow-up. In addition to a clinical examination, the consultation is based on a cervical ultrasound and a biological control by assaying thyroglobulin. This protein is produced only by thyroid tissue. After complete removal of the thyroid, its level should be undetectable. Any presence or increase in the level of thyroglobulin indicates the existence of cancerous foci (metastases). In this case, specific treatment will be necessary (iodine 131, possibly surgery, etc.).
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