Cancer is a disease where cells in the body grow beyond their usual size and become uncontrollable. Cancer can originate from anywhere in the body as a malignant growth and replication on its site of location. There are numerous types of cancers with different names, but today, I will be discussing Thyroid Cancer. Thyroid cancer is cancer of the thyroid gland which is an endocrine gland located at the anterior part of the neck region. The Thyroid gland has a butterfly shape and it releases thyroid hormones which are vital to the body's functions. These hormones include; Triiodothyronine (T3), and Thyroxine (T4) which are responsible for mentation, movement, and metabolism.
Thyroid carcinoma/cancer can be divided into four main types which are the Papillary, Follicular, Medullary Thyroid (MTC), and Anaplastic, other less common thyroid cancers are primary thyroid lymphoma and primary thyroid sarcoma. Thyroid cancer is the 13th most common cancer diagnosis overall, having the sixth most common diagnosis in women. Its incidence rate is about 5.4% in men and 6.5% in women, having a higher incidence in women than men.
Papillary Carcinoma is basically the most common type of thyroid cancer, with about 70 to 80% of all thyroid cancer cases. Follicular Carcinoma accounts for about 10% of all thyroid carcinoma cases, with Hurthle cells carcinoma which is a very rare type of follicular carcinoma, and common in women. Medullary Thyroid Carcinoma accounts for about 8 to 10% of all thyroid cases being part of multiple endocrine neoplasias (MEN) 2A, and MEN 2B conditions, and Anaplastic Carcinoma is the rarest of all thyroid carcinoma, and it is common in older patients. The (Para)Follicular cells and the C- Cells are responsible for Thyroid cancer. The (para)follicular cells are responsible for Papillary, Follicular, and Anaplastic carcinoma, while C-cells are responsible for Medullary thyroid carcinoma.
Thyroid cancer can be caused as a result of several risk factors including radiation exposure such as head and neck radiation exposure, and environmental radiation which could lead to carcinoma, especially papillary carcinoma. If patients have previous therapy for cancer, they are at high risk of developing cancer again. Family History is another risk factor, and although it doesn't amount to a large case of thyroid cancer, it is a risk factor. Another is Genetic Conditions such as MEN 2A and MEN 2B. MEN 2A is associated with three carcinomas such Parathyroid hyperplasia, Medullary Thyroid Carcinoma, and Pheochromocytoma. The MEN 2B is associated with Mucosal Neuromas, Marfanoid body habitus, Medullary Thyroid Carcinoma, and Pheochromocytoma. Being Females is another risk factor for thyroid carcinoma, as females are more likely to have thyroid cancer than males. Age is another risk factor, usually adults in their 60s and 70s.
Signs and Symptoms of Thyroid cancer includes Thyroid Nodule which is a little growth protruding from the thyroid gland. Thyroid nodules are painless, and patients could have solitary nodules or more, which could be non-motile and hard, and not everyone with thyroid nodules suffers from Thyroid cancer but it is a sign of it. Cervical lymph nodes are another sign of Thyroid cancer. The lymph nodes can be swollen and tender in the neck region. The lymph nodes can increase as cancer worsen. Other signs and symptoms include neck swelling, Dyspnea (shortness of breath), voice hoarseness, Dysphagia (difficulty swallowing), and Horner's syndrome which includes Miosis, Anisocoria, and ptosis. Other symptoms that could be constitutional include weight loss, fever, nightmares, and fatigue.
Diagnosing Thyroid Cancer would include examining the head and neck, in cases of Thyroid Nodules can be examined. Another way to diagnose thyroid cancer is Indirect laryngoscopy, Blood Work such as looking at thyroid hormones level, calcitonin level such as in Medullary Thyroid Carcinoma, using Fine-needle aspiration biopsy of the nodule (lobectomy), Genetic analysis (RET mutation in Medullary Thyroid Carcinoma), in cases of papillary thyroid cancer, looking for B-RAF V600E mutation can be performed. Other diagnostic tests would include Thyroid Ultrasonography, Neck, abdominal and pelvis CT or MRI (such as in cases of Metastasis, and mass extension). With the diagnosis, comes the staging of Thyroid Cancer.
The most commonly used staging of thyroid cancer is the American Joint Committee on Cancer (AJCC) which utilizes the Tumor-Node-Metasis TNM classification system. The classification goes thus;
T0 - No primary tumor found
T1 - Tumor found and it is limited to the thyroid. The tumor is no larger than 2cm
T2 - Tumor within 2cm and 4cm, which is limited to the thyroid.
T3 - Tumor greater than 4cm, and is limited to the thyroid, and could involve strap muscles.
T4 - Any size tumor with extrathyroidal cancer extension going beyond the strap muscles.
N0 - No regional lymph node involvement
N1 - Regional involvement of Lymph nodes.
M0 - No distance metastases
M1 - Distant Metasteses
Each of the stage can poccess or not pocess one another. We couls have stages such as: a T1 tumor, with N0 (no lymph node), and M0 (no distant Metastases), and so on.
Treatment of Thyrtoid Cancer includes;
- Surgical excision, which is possible in all types of thyroid cancer, including subtotal/total thyroidectomy
- Radioiodine ablation
- Thyroid hormone suppression therapy
- Lobectomy, isthmectomy, and thyroidectomy for hurthle cell.
- In rare cases, Chemotheraphy and Radiation theraphy.
- Prophylactic central lymph node dissection
While this is treatable, there can be complications in treatment. Complications could arise from surgical excision causing laryngeal nerve injury, hypoparathyroidism as a result of removing the parathyroid glad during surgery.