Thyroid Cancer – Symptoms, Diagnosis and TreatmentheadingContent
September is Thyroid Cancer Awareness Month, and in 2013, the American Cancer Society estimated that 60,220 new cases of thyroid cancer would be diagnosed in the United States, making it the fastest growing cancer in recent years. Although this is partially due to the improvement of our technology which allowed us to see small nodules and small papillary cancers that previously would not have been seen, there is still concern about an increase incidence even in large, symptomatic nodules as well.
What are the symptoms of thyroid cancer?
Thyroid nodules are extremely common in the general population, and during our lifetime, up to 80 percent of us may develop a nodule. Only about 5-10 percent of these nodules will become malignant. Many thyroid cancers are asymptomatic and incidentally discovered; however, the most common symptom is a palpable thyroid nodule. During more advanced stages, patients may become hoarse, have difficulty swallowing or have enlarged lymph nodes.
What are the causes or risk factors for developing thyroid cancer?
It is not clear what causes thyroid cancer. Thyroid cancer arises from mutations in thyroid cells, so any radiation exposure, like head and neck cancer radiation treatment, may be a risk factor. Family history of inherited genetic syndromes, like multiple endocrine neoplasia and familial adenomatous polyposis are also risk factors for developing thyroid cancer.
Females are three times more likely to have thyroid cancer. Thyroid cancer can occur in any age group, although it is most common after age 30, and its aggressiveness increases significantly in older patients.
What are the types of thyroid cancer?
Thyroid cancer can be divided into two types – differentiated and undifferentiated. The most common type of thyroid cancer is papillary, which accounts about 85 percent of differentiated thyroid cancers. Follicular accounts for about 15 percent of differentiated thyroid cancers. Anaplastic thyroid cancer is considered to be undifferentiated, likely arising from differentiated cancers. This cancer is rare but extremely aggressive and difficult to treat.
How do you diagnose thyroid cancer?
Many thyroid nodules are diagnosed during a physical exam, by palpating the thyroid gland and feeling a “lump.” However, some nodules are diagnosed incidentally during imaging initially ordered for something else.
Once a nodule is detected, an endocrinologist will decide whether this nodule needs to be evaluated by a fine needle aspiration. Some nodules may be too small to biopsy or have benign ultrasound characteristics, and the doctor may choose to monitor it rather than ordering a needle aspiration.
There are cases in which the fine needle aspiration does not give us a clear diagnosis of thyroid cancer. We now have the ability to do genetic testing of those cells to determine the presence of mutations, which will help us decide whether surgery is recommended or not.
How do you treat thyroid cancer?
Many patients may undergo a complete thyroidectomy once thyroid cancer is diagnosed. Further treatment will depend on the stage of the cancer, the type of cancer, the age of the patient, overall health and patient preferences. For most Stage 1 differentiated thyroid cancers, radioactive iodine (RAI) therapy is not recommended, unless the patient has many high risk features. RAI therapy is administered orally in attempts to destroy any thyroid tissue that was not removed during surgery. This therapy is usually recommended in more advanced stages of differentiated thyroid cancer. There is a very low risk that this therapy could damage other organs in the body. For medullary thyroid cancers, RAI has no role because it arises from a different type of thyroid cell than papillary and follicular cancers, so surgery is always recommended for this type of cancer.
After surgery, patients require life-long thyroid hormone replacement. It is very important to follow-up with an endocrinologist, as there are specific guidelines on how much thyroid hormone replacement is required after the surgery.
Most patients with differentiated thyroid cancer may be cured with surgery and/or RAI therapy, but in some rare instances other treatments may be necessary.
What is the prognosis of thyroid cancer?
Most thyroid cancers can be curable. In fact, the most common types of thyroid cancer (papillary and follicular) are the most curable. In younger patients, both papillary and follicular cancers have more than 97 percent cure rate, if treated appropriately. Close monitoring and following-up with an endocrinologist is recommended.
Medullary thyroid cancer is significantly less common, but may have a worse prognosis. This cancer can require extensive surgical excision of the thyroid gland and neck lymph nodes.
Anaplastic thyroid cancer is extremely rare, but can be extremely aggressive with a very poor prognosis. Very few patients have survived anaplastic thyroid cancer, as most have extensive metastasis at the time of diagnosis.
What about long term management?
Long term management will depend on the stage of thyroid cancer; some patients may require closer monitoring and follow-up. An endocrinologist will decide what type of imaging or blood tests are required during the first five years after surgery. Patients that have had excellent response to treatment with no evidence of recurrence during the first five years will have a decrease in the intensity and frequency of follow up visits. Patients that have had an incomplete or indeterminate response will have a much tighter follow-up, until there is no longer evidence of recurrence.
Thyroid cancer is now considered one of the most rapid growing cancers. Luckily, the cure rate for differentiated thyroid cancer is very high. The key to a complete cure lies in early detection, appropriate treatment at time of diagnosis and close follow-up with an endocrinologist until complete remission is achieved.