Differentiated Thyroid Cancer

Differentiated Thyroid Cancer

Papillary and follicular thyroid cancers are referred to as differentiated thyroid cancer, which means that the cancer cells look and act in some respects like normal thyroid cells. Their variants include columnar, diffuse sclerosing, follicular variant of papillary, Hürthle cell, and tall cell. Two other variants (insular and solid/trabecular) are considered to be intermediate between differentiated thyroid cancer and poorly differentiated thyroid cancer. The variants tend to grow and spread more than typical papillary cancer.

Incidence:

The nationwide relative frequency of thyroid cancer among all the cancer cases was 0.1%–0.2%. The age-adjusted incidence rates of thyroid cancer per 100,000 are about 1 for males and 1.8 for females as per the Mumbai Cancer Registry, which covered a population of 9.81 million subjects. Out of this, 90-95% of the cases are differentiated thyroid cancer, papillary and follicular thyroid carcinoma.

Thyroid Cancer

Signs & Symptoms:

Tracheal compression or invasion by thyroid cancer can result in hoarseness of voice, dyspnea or cough, especially with exertion or in the recumbent position, or hemoptysis. Esophageal compression or invasion by thyroid cancer will cause dysphagia at the level of the lower neck to solids and pills, but not to liquids. In order to feel a thyroid nodule, it is important to know where it is located in the anterior neck. Thyroid nodules can be soft to palpation and may not be easily identified on exam.

Diagnosis:

  • Biopsy: Cells from the suspicious area are removed and looked under the microscope. Usually, this test is done after blood tests and ultrasound.
  • Imaging test: This is usually done to help find suspicious areas that might be cancerous, to learn how far cancer has spread and to help determine if the treatment is working or not.
  • Ultrasound: This test helps conclude if a thyroid nodule is solid or filled with fluid (solid nodules are likely to be cancerous.) It can also be used to confirm the number and size of the thyroid nodules.
  • Chest X-ray: Helps find out if the cancer has spread to the lungs or not.

Treatment:

  • Thyroid Surgery – The thyroid tumor is staged in order to develop the most effective treatment plan. The two types of surgeries which can be performed are Hemi thyroidectomy and Total thyroidectomy.
  • Radioactive iodine treatment- Radioactive Iodine-131 is used in patients with papillary or follicular thyroid cancer for ablation of residual thyroid tissue after surgery and for the treatment of thyroid cancer
  • External radiotherapy
  • Chemotherapy and targeted therapies – medications used to kill cancer cells
  • There are additional treatment modalities, such as radiofrequency ablation, and percutaneous ethanol (alcohol) injections, for selected circumstances used in other countries, which can used by India.

Points to keep in mind:

  • Treatment aims to remove all or most of the cancer and help prevent the disease from recurring or spreading.
  • Treating thyroid cancer often uses two or more of these treatment approaches.
  • Discuss your situation and your treatment with your physician so that you understand what is recommended and why.

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Prognosis:

In younger patients less than 50 years of age, both papillary and follicular cancers have a more than 98% cure rate if treated appropriately. Both papillary and follicular thyroid cancers are typically treated with at least complete removal of the lobe of the thyroid gland that harbors the cancer.  A thyroid gland that has a thyroid cancer nodule within it and has multiple other nodules in both sides of the thyroid or when the cancer has spread to lymph nodes in the neck, is a clear indication for complete removal of the thyroid gland.

Recent Advances:

  • Endoscopic Thyroid Surgery

Endoscopic thyroid surgery was first described in 1997 by Huscher. This technique, popularly known as minimally invasive video assisted thyroidectomy (MIVAT) is the most widely accepted endoscopic technique.

  • Robotic Thyroid Surgery

In general, conventional endoscopic surgeries have some limitations in obtaining adequate visualizations and precise, meticulous manipulation of the surgical tissues. These limitations result from the two-dimensional representation and the simplicity of the endoscopic instruments used. The da Vinci S surgical robot system (Intuitive Surgical, Sunnyvale, CA, USA) was developed to address these limitations of conventional endoscopic surgery This procedure was initially described by Kang and avoids the use of a neck incision altogether. However, it has been shown that operative times are longer, and there is a significant learning curve for the procedure