Thyroid Cancer Papillary

Papillary cancer is the most common, and most treatable, type of thyroid cancer. Most people with papillary thyroid cancer can be completely cured with surgery. There are more than 10,000 new cases of papillary thyroid cancer diagnosed in the United States every year. In fact, papillary cancer comprises at least 70% of all diagnosed thyroid cancers. Most people develop papillary thyroid cancer before age 40, and it is much more common in women than in men, although the reason for this is not understood.

The majority of people with papillary thyroid cancers do not even know they have the disease until a doctor notices a painless thyroid lump. Occasionally, a thyroid lump may be too small to feel, but instead, you or your doctor may notice an enlarged lymph node or gland in your neck which does not shrink. There are lymph nodes all over your body that help to fight infection and the nodes near an infected area tend to become enlarged until the infection is gone. You may notice that the lymph nodes in your neck right under your jaw bones tend to become enlarged when you have a sore throat and shrink when you are feeling better. However, if the glands do not become smaller in a few weeks, that could be a signal that the lymph glands are abnormal.

Diagnosis

The majority of papillary thyroid cancers can be diagnosed by performing a fine needle aspiration biopsy, which involves removing fluid from the thyroid lump or enlarged lymph node using a small needle. The cells within the fluid are then examined by a pathologist to identify characteristic features of papillary thyroid cancer cells. The microscopic features that are unique to papillary thyroid cancer cells are changes within the nucleus (the part of the cell that holds the DNA and genetic material). Normally this nucleus is dark and round, but with papillary thyroid cancer there can be large clear areas within the nuclei which look like "Little Orphan Annie" eyes. These changes are called "optically clear nuclei" and are, for the most part, diagnostic of papillary thyroid cancer (fig 3).

In addition, some nuclei may appear to have a line or groove in them. This appearance is called "nuclear grooving" and is also highly diagnostic for papillary thyroid cancer. Other features of the fine needle aspirate which would suggest papillary thyroid cancer but which are not diagnostic for it include the presence of psammoma bodies, which are spiral rings of calcifications (fig 3), or the presence of papillary fronds which look like the fronds of a fern plant (fig 2). A fine needle aspiration biopsy is over 90% accurate if the above mentioned features are present and if the biopsy is performed by an experienced physician and examined under the microscope by a skilled pathologist.

Microscopic views of normal thyroid tissue versus papillary thyroid cancer
Fig 1. Normal thyroid tissue	Fig 2. Papillary cancer (low resolution). Notice the frond-like projections.	Fig 3. Psammoma body within a papillary cancer. Optically clear nuclei are circled in blue.

Treatment

Surgery is currently the only tested treatment option to cure papillary thyroid cancer. Most people can be cured by surgical removal of the thyroid gland. Once the diagnosis of papillary thyroid cancer has been made by fine needle aspiration biopsy, surgery is indicated in order to remove the tumor. There are differing opinions among surgeons regarding the amount of thyroid tissue that should be removed from a patient with papillary thyroid cancer. Removing one lobe (or "wing of the butterfly-shaped gland) is called a lobectomy. If the surgeon chooses to do a lobectomy only, it is important to examine the opposite lobe via ultrasound to be sure that there are no nodules present. This may help the patient in making a decision about the extent of surgery. Removing almost the entire gland on both lobes is called a subtotal thyroidectomy, and removing the entire gland is called a total thyroidectomy.

The extent of the surgery performed depends on individual features of the tumor as well as the judgment the surgeon makes during surgery in order to determine if the papillary thyroid cancer has spread to the opposite lobe or to the lymph nodes in the neck. More extensive surgery is associated with higher complication rates and thus many surgeons who are inexperienced in thyroid surgery choose to remove less thyroid tissue in order to decrease the complication rates. If you have had a history of head and neck irradiation, removal of the entire thyroid gland is recommended because you may have lumps on both sides of your thyroid gland. Cancer may occur anywhere within the thyroid, not just in the large lumps. In general, our preference 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.

If neck lymph nodes are enlarged as a result of papillary thyroid cancer, you will need to have them removed in an operation called a modified radical neck dissection. This operation involves removing the lymph nodes along one side of the neck. After the operation, this area of the neck is usually numb 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 sides of the neck must be cleared of lymph nodes. If this is the case, two separate operations are performed about 2 months apart. This delay is to allow time for healing on one side before beginning the operation 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 in between operations to allow for alternate pathways of blood and lymph flow to form in order to drain the head and neck area.

Follow Up

There is also controversy about the way you should be followed by your physician after surgery for papillary thyroid cancer. There are many different tests available to try to identify cancer recurrences in the neck and elsewhere in the body such as lung or bone. One of the best and still least expensive tests is a careful physical examination by a practitioner skilled in thyroid disease. Because papillary thyroid cancer tends to spread to lymph nodes in the neck rather than other far away areas such as lung or bone, a careful physical examination can easily detect a recurrence in a neck lymph node(s). In addition, your physician may order an ultrasound of the neck to look for enlarged lymph nodes as well as a simple blood test called thyroglobulin which may be elevated if the cancer comes back. An operation can remove these affected nodes and provide a complete cure. Other tests used to detect metastatic disease include radioactive iodine scanning, ultrasound, serum thyroglobulin levels and sestamibi scanning.

Many people want to take an active role in their recovery from thyroid cancer. We advise a healthy lifestyle and diet, including regular exercise, 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. Another important aspect of your daily regimen is maintaining a positive attitude, which will help your overall health as well as your long-term outlook.

If you have undergone surgery for papillary thyroid cancer, you will benefit from taking thyroid hormone medication for the rest of your life. The thyroid hormone 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 manufacture thyroid hormone). This is important because if TSH is left at high levels, it will stimulate both the remaining normal thyroid as well as any thyroid cancer and metastases to grow and enlarge. Thus, by taking thyroid hormone medication, TSH is suppressed and thyroid cancer growth is avoided. 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 every two months shortly after surgery until a stable dose has been achieved and then less frequently.

It was once believed that patients with a history of thyroid cancer needed to take very high doses of thyroid hormone medication. These high doses may have some undesirable and dangerous side effects such as the development of heart disease and/or osteoporosis, and new studies have shown that these high doses are not needed to prevent cancer recurrence in most instances. Instead, a dose of medication close to the normal range may be just as effective in preventing recurrent or metastatic disease. Ask your doctor what is your correct individual dose.

Recurrence of Cancer

If your doctor discovers a new lump in your neck or if one of your blood tests or X-rays is abnormal, the cancer may have returned. This happens very infrequently, but if it does, there are many treatment options available. If a cancer recurrence is detected in your neck lymph nodes, the best course of action is usually an operation to remove the affected node or nodes, as described above. Other treatment options include radioiodine therapy. Radioactive iodine is given as a pill and this iodine is taken up by thyroid cancer metastases and the radioactivity destroys them (without harming other parts of your body).

One problem with this treatment is that normal thyroid tissue attracts the radioactive iodine much more efficiently than does thyroid cancer metastatic disease. Therefore you can only undergo this type of treatment if you have had your entire thyroid gland removed. If you've been treated with removal of just part of your thyroid gland, the remaining normal thyroid gland will interfere with this therapy. Thus, you must undergo reoperation to remove the remaining gland or initial radioactive iodine treatment with a low dose of medication in order to wipe out the normal thyroid before proceeding with a larger dose to eradicate the thyroid cancer. If you have not had your entire thyroid removed, but need to be treated with radioactive iodine, you can receive this initial lower dose about six to eight weeks after your thyroid surgery. (See the section on radioactive iodine treatment)