Thyroid nodules and cancer

Nodules are typically small lumps on the thyroid, an endocrine gland situated in the center of our neck that resembles a butterfly in shape. Nodules are quite prevalent, with around half of the population having at least one thyroid nodule, often without being aware of it. The majority of nodules, approximately 95%, are non-cancerous. The primary purpose of examining them is to eliminate the possibility of cancer and, naturally, to address it promptly.

What symptoms do nodules cause?

Most nodules do not present any symptoms and are often discovered by chance during a physical examination or imaging test. Some nodules become overactive, producing more hormones than the thyroid typically does, leading to hyperthyroidism. Hyperthyroidism results in a rapid heartbeat, weight loss, restlessness, and insomnia, symptoms that can often mimic common anxiety. Nodules causing hyperthyroidism are never cancerous, but they do require treatment. In rare cases, some nodules may grow large enough to be noticeable or cause difficulty swallowing. Malignant nodules seldom cause symptoms.

How are thyroid nodules investigated?

The primary aim of examining thyroid nodules is to distinguish the benign ones, which only require monitoring or treatment if they are overactive, from the malignant ones, where early detection leads to a favorable outcome through specific surgical intervention.

Laboratory and imaging tests assist in making this distinction:

– Blood tests: A simple TSH measurement can distinguish hyperfunctioning nodules if the level is low. This is important as hyperfunctioning nodules are benign, yet they still require treatment. Measuring calcitonin is also crucial, as a low level can exclude medullary thyroid carcinoma, a severe type of cancer. Other thyroid blood tests are not particularly useful for examining nodules but are more relevant in diagnosing autoimmune Hashimoto's thyroiditis, which is a separate condition.

– If hyperfunction is indicated, the subsequent test is a thyroid scintigraphy. During this procedure, nodules are categorized as hot or cold. Hot nodules produce hormones and are generally not harmful, but they require treatment if they lead to hyperthyroidism. A small number of cold nodules might be malignant.

– Thyroid ultrasound: This is a crucial medical test that should be conducted by a specialist. It is painless, free of radiation, and can lead to a diagnosis when performed by a skilled radiologist. Specific radiological criteria help distinguish between benign and malignant nodules on the ultrasound. For nodules deemed suspicious according to these criteria, the subsequent examination is…

– Fine-Needle Aspiration (FNA):Through this procedure, conducted with a fine needle and guided by ultrasound, the doctor collects a sample from the nodule to send for cytological analysis. This safe examination helps determine the subsequent treatment for the nodules.

Nowadays, the results of cytological examinations of nodules are categorized into specific categories, unlike in the past when they were simply labeled as “good” or “bad.” This categorization is very important for making treatment decisions.

In previous decades, a significant number of surgeries in our country were unfortunately conducted without any medical justification. This was partly due to the lack of the categorization system that is now in place.

The results of cytology, which come with a certain percentage of potential error that should be discussed with the patient, can fall into one of the following categories:

– Non-diagnostic: In this case, a repeat biopsy is recommended. To minimize these results, it is recommended that the examination be performed by an experienced radiologist and cytologist.

– Benign

– Intermediate/Unclear: In this case, molecular testing or repeat biopsy is recommended. Molecular testing is becoming increasingly available in our country and greatly helps our decisions in this category.

– Suspected malignancy

– Malignant

Considering the FNA results and blood calcitonin levels, nodules are classified into those needing only monitoring and those requiring surgical removal. It's important to note that treating nodules with thyroxine (similar to hypothyroidism treatment) lacks scientific support and may cause negative effects like arrhythmias, irritability, and osteoporosis.

Surgical treatment by a specialist Endocrine Surgeon is the cornerstone in the treatment of nodules classified as malignant.

Thyroid Cancer: Types, Treatments, and Risk Factors

Thyroid cancer is the most common malignancy of the endocrine system (95% of all) and 1.5-3% of all malignant neoplasms of the human body. Women are affected more often than men in a ratio of 3 to 1, mainly between the ages of 25 and 65, with the lifetime risk of developing the disease being 0.8 and 0.3 for women and men respectively.

Over the past ten years, it has demonstrated the highest yearly rise in the incidence of a neoplasm compared to all other malignant diseases affecting different organs. This is likely attributed to environmental factors, as well as significant advancements in diagnostic methods.

Thyroid cancer is categorized based on its origin. Consequently, there are malignant diseases that arise from the follicular cells of the gland and those that develop from the non-follicular cells.

In the first category we find the papillary type (85% of the total), the follicular type (12% – which also includes Hurthle cell lesions) and the anaplastic type (1 – 2%).

The second category includes medullary carcinoma (4 – 5%), thyroid lymphoma (2%), teratoma and metastases from malignant diseases of other organs (exceptionally rare cases).

Once a diagnosis is confirmed or there is a strong suspicion of malignancy, the endocrinology team devises a treatment plan aimed solely at curing the condition and minimizing the risk of recurrence or metastasis. Treatment for all types of thyroid malignancy (except lymphoma) involves surgery, specifically the complete removal of the gland with no functional postoperative residue (total thyroidectomy – either classic or minimally invasive). This procedure is accompanied by the removal of cervical lymph nodes (central – ipsilateral or bilateral functional radical lymphadenectomy) if they are affected or if there is a clear clinical, laboratory, and/or imaging suspicion.

Following surgery, the endocrinologist works together with the nuclear medicine team when necessary. In some cases, depending on the type of thyroid cancer, a therapeutic dose of radioactive iodine is given to eliminate any remaining malignant cells and/or lymph node micrometastases.

The treatment plan is finalized with the administration of suitable medication. External radiation may be used as a preoperative or supplementary treatment for anaplastic carcinomas, while chemotherapy is rarely employed and is primarily reserved for anaplastic cases, either before or after surgery.

Following the operation and any further treatments, the patient is regularly monitored by the endocrinology team to detect any potential recurrence early. With adherence to the appropriate therapeutic protocol and if the surgery is conducted by a surgeon specialized in oncological surgery of the endocrine glands, the prognosis is excellent in the vast majority of cases (99%), leading to a cure.

(Emmanuel A. Tsigos, a thyroid surgeon, contributed to the writing of the article. The article was originally published on ygeiamou.gr on 4/10/2022.)