There are three main parts to the treatment of papillary thyroid cancer:
The best treatment for papillary thyroid cancer is almost always total thyroidectomy (i.e. removal of the entire thyroid). There are a few very specific situations in which some doctors will remove only the half of the thyroid with the cancer (i.e. thyroid lobectomy), but most doctors recommend a total thyroidectomy because:
- Most papillary thyroid cancers are multifocal (i.e. in more than one part of the thyroid)
- Post-operative RAI ablation therapy is more effective if there is no normal thyroid tissue to soak up the radiation.
- Follow-up for recurrence (i.e. cancer that comes back) with the thyroglobulin blood test is more accurate. Thyroglobulin is a protein made by thyroid cells, both cancerous and normal. Without any normal thyroid tissue, the thyroglobulin level should be close to zero and if it rises, then it is likely that the cancer has come back. If there is half of a normal thyroid gland left in place, then the levels are harder to interpret and if the level rises, it will be unclear if the cancer has come back or if the normal thyroid lobe is growing.
- The recurrence rate (i.e. chance that cancer comes back) is lower in patients who have had a total thyroidectomy than a lobectomy.
In general, our preference at the Thyroid Center is to remove the entire thyroid gland in order to prevent the cancer from returning or spreading to the opposite side — but the extent of surgery is ultimately up to the patient. Prior to the operation, a lymph node mapping (i.e. an USG exam of the central and lateral compartments of the neck) should be done to see if there are suspicious lymph nodes that may need to be removed along with the thyroid. The most common location to have involved lymph nodes is in the central neck compartment (i.e. the lymph nodes surrounding the thyroid). If there are suspicious looking nodes on lymph node mapping or on inspection in the operating room, a therapeutic central neck dissection (i.e. removal of the central neck lymph nodes) should be performed. Some surgeons suggest removing all of the central neck lymph nodes regardless of whether or not they are suspicious looking in an operation called a prophylactic central neck dissection in order to lower the recurrence rate. However, most surgeons believe that a central neck dissection should only be done if there are suspicious looking lymph nodes because:
- The recurrence rate is essentially the same
- The complication rate is significantly higher in prophylactic central neck dissections versus therapeutic central neck dissections. See Thyroid Surgery > Risks of Thyroid Surgery
Risk of Complications With
Prophylactic vs Therapeutic Central Neck Dissection
If the lateral neck lymph nodes (i.e. the lymph nodes surrounding the carotid artery and jugular vein) are involved with papillary thyroid cancer, then an operation called a modified radical neck dissection will be performed either at the time of the total thyroidectomy or in the future. This operation involves removing the lymph nodes along one side of the neck. After the operation, this area of the neck is usually numb for a period of time because the nerves to the skin in this area are purposely severed in order to remove the diseased lymph nodes. Other than this numbness, there are no long-term effects of having these lymph nodes removed.
Sometimes both the left and right lateral neck lymph nodes are involved with cancer. If this is the case, then modified radical neck dissections on one side and then the other are performed about 2 months apart. This delay is to allow time for healing on one side before operating on the opposite side. Performing the lymph node dissection on both sides at the same time could lead to unnecessary swelling (edema) of the head and face if time is not given between operations for alternate pathways of blood and lymph flow to form.
Thyroid Hormone Suppression:
After removal of the entire thyroid, patients will need to take thyroid hormone replacement pills (usually one pill a day for the rest of their lives) in order to replace the hormone that the thyroid would normally make. Patients with thyroid cancer are typically given a slightly higher dose than patients without thyroid cancer in order to suppress or block any stimulation for thyroid cancer cells to grow. The thyroid hormone replacement pill tricks the brain into thinking that enough thyroid hormone is being manufactured by the thyroid gland, therefore shutting down the brain's production of TSH (thyroid stimulating hormone which normally encourages the thyroid to make thyroid hormone). This is important because if TSH is left at high levels, it can stimulate both the remaining normal thyroid as well as any thyroid cancer and metastases to grow and enlarge. The thyroid hormone suppression dose for cancer is usually calculated to be 2 mcg/kg. In order to maintain a dose of thyroid hormone that is right for you, blood tests for thyroid function will need to be checked periodically. Generally, these blood tests are done every two months after surgery until a stable dose has been achieved, after which they may be done less frequently. Ask your doctor what is your correct individual dose.
Radioactive Iodine (RAI) Ablation:
Depending on the final pathology, the patient may need RAI ablation or what some doctors call remnant ablation. RAI ablation is not like the traditional external beam radiation which can be difficult on patients. RAI ablation is a pill that is taken once and usually causes few side effects. In this therapy, radioactive iodine is given to destroy any remaining thyroid cells (both cancer and benign) after total thyroidectomy. RAI ablation does not improve the overall excellent prognosis, but rather, it decreases the recurrence rate (i.e. chance of cancer coming back). Patients with papillary thyroid cancer larger than 4 cm in size, extrathyroid invasion (i.e. thyroid cancer that grows outside of the thyroid into surrounding tissue), thyroid cancer in lymph nodes (i.e. positive nodes), and/or thyroid cancer that has spread to other parts of the body (i.e. metastases) should have RAI ablation after total thyroidectomy. In general, papillary thyroid cancers less than 1 cm in size without positive nodes or extrathyroid invasion do not usually require RAI ablation. Patients with papillary thyroid cancers between 1 and 4 cm in size and/or that are multifocal should discuss with an experienced thyroid cancer specialist whether or not RAI ablation is needed. See RAI ablation ».
Fortunately, patients with papillary thyroid cancer rarely need chemotherapy or traditional external beam radiation therapy. External beam radiation is typically used in cases where the cancer has invaded into surrounding structures like the esophagus or windpipe (i.e. trachea). Finally, many people want to take an active role in their recovery from thyroid cancer. The Thyroid Center advises a healthy lifestyle and diet, including decreased alcohol consumption, avoiding cigarette smoking, and eating a diet which is low in fat and high in fiber. These changes are recommended to reduce many types of cancers, not just thyroid.