Papillary thyroid cancer is the most common of all thyroid cancers (>85%). It can also be called “papillary thyroid carcinoma” since carcinoma implies a certain type of cancer. Since thyroid cancer is relatively common, and papillary thyroid cancer is the most common form of thyroid cancer, it is very likely that you will know somebody that had or has this form of cancer. Papillary thyroid cancer typically starts within the thyroid as growth, or bump (nodule) on the thyroid that grows out of the otherwise normal thyroid tissue. Papillary thyroid cancer is clearly increasing in its incidence both in the United States and globally--it is one of the few cancers that are becoming more common, but we don't know why this is happening. Our Introduction to Thyroid Cancer page has a great general overview of all types of thyroid cancer--read it if you haven't already!
Papillary Thyroid Cancer Quick Facts:
- Peak onset ages 30 through 50
- Females more common than males by 3 to 1 ratio
- Prognosis directly related to tumor size [less than 1.5 cm (1/2 inch) very good prognosis]
- Accounts for 85% of thyroid cancers
- Can be caused by radiation or x-ray exposure
- Spread to lymph nodes of the neck present in up to 50% of cases
- Distant spread (to lungs or bones) is very rare
- Overall cure rate very high (near 100% for small papillary cancers in young patients)
Papillary Thyroid Cancer: Who Gets It?
Papillary thyroid cancer (carcinoma) can occur in people of all ages from early childhood to advanced ages although it is most common in people between age 30 and 50. Papillary thyroid cancer affects women more commonly than men, and it is most common in young women. Thyroid cancer is now the fifth most common malignancy among women (and 17th among men) in the United States. Since it can occur at any age, everybody should be aware of any changes in their thyroid gland and make sure their doctor feels the thyroid gland when getting a routine check-up. For more details on who gets papillary thyroid cancer, the increasing incidence, and ages of patients affected, go to our page on the Incidence of Papillary Thyroid Cancer.
Papillary Thyroid Cancer: How is it Diagnosed?Papillary thyroid cancer starts as a growth of abnormal cancer cells within the thyroid. As these cells multiply they form a bump or "nodule" within the thyroid that often sticks out of the side or front of the thyroid gland. For this reason, most papillary thyroid cancers, like all thyroid cancers, are diagnosed after a doctor feels the neck of a patient. Usually the doctor stands behind the patient to feel the thyroid for nodules or bumps. Sometimes, these growths and nodules can be seen when looking at the neck of thin women as a small bump under the skin that moves when the person swallows. Sometimes people are undergoing scans or x-rays of the neck for some other reason and a nodule or worrisome area of the thyroid is seen. Either way, your physician feeling this mass or seeing it as a surprise on some other scan will typically order a thyroid ultrasound to look at the thyroid closely and take pictures of the mass or nodule. If the nodule has some worrisome characteristics the next step is almost always a needle biopsy. We have several pages on needle biopsies of thyroid nodules. If you have recently undergone a thyroid needle biopsy or are scheduled to have a needle biopsy, this page is for you. (Cooper DS, Doherty GM, et al. Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2009 Nov;19(11):1167-214.)
Papillary Thyroid Cancer: What About Lymph Nodes?
We have lymph nodes all over our body that are made up of groups of infection-fighting and cancer-fighting immune cells. We all have had "swollen glands" in our neck when we had a sore throat or tonsils. These same glands that get swollen when we have a neck infection can help fight cancer by preventing the cancer cells from spreading from the thyroid to the rest of the body. It is common for papillary thyroid cancer to spread into the lymph nodes of the neck before the cancer is discovered and diagnosed. Again, since there usually aren't any symptoms, the cancer grows slowly for years and has time to spread into the lymph nodes, which are doing their job of capturing the cancerous cells before they can spread further. Thus, cancer that has spread into the neck lymph nodes is common with papillary thyroid cancer and may occur in as many as 40 percent of patients with small papillary cancers. In patients with larger papillary thyroid cancers, lymph node spread (metastases) within the neck lymph nodes may occur in up to 75 percent of cases.
The presence of lymph node metastasis in the neck may be associated with a higher chance that the cancer comes back months or years later (a higher recurrence rate). However, having papillary thyroid cancer spread to neck lymph nodes does not necessarily mean that there is a higher mortality rate. In fact, among patients less than 45 years of age, even with spread to neck lymph nodes, survival rates of papillary thyroid cancer exceed 97%. Distant metastasis (spread to other organs of the body) is uncommon for papillary thyroid cancer. (Chen, H and Udelsman, R. Papillary Thyroid Carcinoma. Justification for total thyroidectomy and management of lymph node metastases. Surg Oncol Clin N Am. 1998; 7: 645-664). The overview of the importance of lymph nodes in papillary thyroid cancer ends here, but if you have this problem, then please continue reading our page on Papillary Thyroid Cancer Staging.
Papillary Thyroid Cancer Staging
Papillary thyroid cancers are not all alike. Some are big and some are small. Some have spread to lymph nodes and some have not. To separate out the cancers that are easy to cure from those that are more difficult to cure, doctors have come up with a grading or "staging" system. All cancers have their own staging system, but papillary thyroid cancer has a staging system that is not like other cancers. This staging system for papillary thyroid cancer takes into account the age of the patient. The staging system also includes the size of the papillary thyroid cancer in the thyroid gland itself and whether or not the cancer has spread into lymph nodes around the thyroid or sides of the neck. The staging system for papillary thyroid cancer also includes whether or not the cancer has spread into the fat and muscles around the thyroid (called local extension). Finally, this staging system includes the “differentiation” of the cancer which is what it looks like under a microscope and whether or not the thyroid cancer cells look mature or young and more “angry”. The last component of papillary thyroid cancer staging is the presence of distant metastases, which means whether the cancer has spread to distant (far way) areas like the lungs. If you or someone you know has papillary thyroid cancer, then please read our more detailed page on Papillary Thyroid Cancer Staging. The stage of the cancer will determine how aggressive the operation needs to be, and other things like whether or not radioactive iodine should be given.
Surgery for Papillary Thyroid Cancer
Papillary thyroid cancer is treated with surgery. It is important to understand that the best chance of cure is to have an expert thyroid cancer surgeon from the beginning. A surgeon who performs surgery for papillary thyroid cancer on a daily basis has a higher cure rate than a surgeon who performs thyroid surgery several times per week, or does other types of thyroid surgery (like for goiters). Surgery for thyroid cancer has become very specialized, so it is important for you to be comfortable with your choice of surgeon.
Surgery for papillary thyroid cancer is filled with a number of choices. If the cancer is big (over 1.5 cm or 3/4 inch) then the entire thyroid needs to be removed. However, there is controversy over how much thyroid should be removed if the cancer is small. Some expert thyroid surgeons contend that if the cancer is small and not invading other tissues (the usual case) then simply removing the half of the thyroid (called the thyroid lobe) which contains the cancer will provide as good a chance of cure as removing the entire thyroid. Other surgeons prefer the older method of removing the entire thyroid for all papillary thyroid cancers. How much surgery is performed has an important impact on how you are managed afterwards, how much thyroid hormone you need and many other factors. Because there are many choices to make, it is important that you have a surgeon that understands every option and how it will affect your overall cure rate, whether more surgery will be needed in the future, and many other things. Get the best thyroid cancer surgeon that you can! (Shah JP, Loree TR, et al. Lobectomy versus total thyroidectomy for differentiated carcinoma of the thyroid: a matched pair analysis. American Journal of Surgery. 1993; 166: 331-335.)
After Surgery: Radioactive Iodine and Long-Term Follow up
Almost all people who had surgery for papillary thyroid cancer will need to see a doctor for many years to have exams and certain blood tests to make sure the cancer has been cured, and to detect any return of the cancer as soon as possible should it return. Many people with papillary thyroid cancer will need to take radioactive iodine to help cure the cancer. We have several very important pages on these topics.