Age at diagnosis is an important factor, and the worsening effect of age on the disease increases with age. The earlier a patient is diagnosed, the better the prognosis. Pregnancy does not appear to worsen the prognosis of a patient with thyroid cancer. Women, on the other hand, are more likely to survive their diagnosis. Additional risk factors for an adverse prognosis include the presence of extraglandular extension or the gross invasion of the tumor capsule.
The second most common type of thyroid cancer is called follicular thyroid cancer, which accounts for approximately 10 percent of all thyroid cancer cases. Follicular cancer develops in follicular cells in the thyroid and is less likely to spread to the lymph nodes. Despite this, it can spread to the brain, bones, and lungs. Follicular cancer typically presents as a painless thyroid lump. Most patients with this type of cancer are older than 50. A 2-1 gender ratio is reported for women with follicular cancer.
Thyroid cancer is categorized into two types, adenomas and carcinomas. Adenomas and carcinomas are monoclonal tumors that lack a true capsule. Adenomas and colloid nodules can be either monoclonal or polyclonal. The difference between adenomas and tumors is the cell type. The latter type has a polyclonal nature and is considered malignant.
The most common treatment for anaplastic thyroid carcinoma is a total thyroidectomy. It is important to note that radioactive iodine therapy is ineffective in treating undifferentiated cancer cells. However, external beam radiation therapy can shrink a tumor. Sometimes anticancer drugs are prescribed as a complementary therapy to surgery. The drugs used in chemotherapy may be effective in treating this type of thyroid cancer. You should discuss your treatment options with your doctor to find out what treatment will best work best for you.
The next step in treatment for anaplastic thyroid cancer involves chemotherapy. This involves a drug that is either injected into the vein or taken orally. Chemotherapy may be added to radiation therapy in anaplastic thyroid cancer. A newer class of drugs, called kinase inhibitors, target changes in the cells that cause cancer. These drugs stop protein kinase from telling other cells how to grow. They may even prevent tumors from forming new blood vessels.
Most types of thyroid cancer are associated with chromosomal rearrangements and deletions of the NTRK1 gene. The TP53 tumor suppressor gene is often affected by mutations and alterations in RAS. Although these changes may increase the risk for thyroid cancer, they are still a small part of the overall risk of developing the disease. The chromosomal rearrangements associated with thyroid cancer are reported in Figure 18-11.
Ultrasound scans are another option for diagnosing a thyroid cancer. An ultrasound uses sound waves to take detailed pictures of the thyroid gland. An MRI uses radio waves to examine the thyroid gland. These tests are not able to detect cancers or metastases, but can detect tumors. The type of treatment depends on the size of the tumor, the spread of the disease, and whether it has metastasized. If the tumor is small, a thyroidectomy may be the best treatment option. A patient may also need to remove lymph nodes if the cancer spreads beyond the thyroid.
