Papillary Thyroid Cancer

Papillary thyroid cancer (PTC) arises in the hormone-producing follicular cells of the thyroid gland. Located at the base of the neck, the thyroid helps regulate many essential functions, including metabolism, heart rate, body temperature and energy use. PTC typically grows slowly and often remains confined to the thyroid for many years, although it can spread to nearby lymph nodes. Even when lymph node involvement is present, long-term outcomes are often excellent with appropriate treatment.

Papillary thyroid cancer is the most common type of thyroid cancer, accounting for approximately 80% to 85% of all diagnoses. Although it can develop at any age, it is diagnosed most often in adults between 30 and 50 years old and is more common in women than men. Ongoing advances in imaging, molecular testing and individualized treatment continue to improve diagnostic precision while helping many patients achieve excellent long-term outcomes.

Causes and risk factors for papillary thyroid cancer

Researchers have identified several factors associated with an increased risk of PTC. Even so, many patients have no identifiable risk factors, and the presence of one or more does not necessarily lead to the disease.

Some risk factors cannot be changed, while others involve environmental or other potentially modifiable exposures. Nonmodifiable risk factors for PTC include:

• Female sex – Papillary thyroid cancer affects significantly more women than men.
• Age – Although PTC can develop at any age, it is most frequently diagnosed during early and middle adulthood.
• Family history – Having one or more close relatives with papillary thyroid cancer or certain inherited genetic syndromes may increase the risk.
• Inherited genetic conditions – Rare hereditary syndromes, such as familial adenomatous polyposis (FAP), Cowden syndrome and DICER1 syndrome, are associated with an increased risk of PTC.

Potentially modifiable risk factors for papillary thyroid cancer include:

• Exposure to ionizing radiation – Exposure involving the head or neck, particularly during childhood, is one of the strongest known risk factors for papillary thyroid cancer.
• Excess body weight – Some studies suggest obesity may modestly increase the risk of developing papillary thyroid cancer.
• Iodine intake – Extremely low or excessive iodine intake may influence thyroid health in certain populations, although iodine deficiency is uncommon in the United States.

Signs and symptoms of papillary thyroid cancer

PTC may cause few or no noticeable symptoms, especially during the early stages. In many cases, the cancer is discovered after a thyroid nodule is identified during a routine physical examination or an imaging study performed for an unrelated reason. When symptoms do occur, they often depend on the size of the tumor and whether it has spread beyond the thyroid.

Symptoms of early-stage papillary thyroid cancer

Early warning signs of PTC may include:

• A painless lump or nodule in the front of the neck
• Visible swelling in the lower front of the neck
• Enlarged lymph nodes in the neck
• A feeling of fullness or pressure in the neck

Signs of advanced papillary thyroid cancer

As the tumor grows and extends beyond the thyroid, additional symptoms may develop, such as:

• Persistent hoarseness or other voice changes
• Difficulty swallowing or the sensation that food is getting stuck
• Shortness of breath or difficulty breathing
• Neck pain that may radiate to the ears
• A persistent cough unrelated to a cold or another respiratory illness
• Progressively enlarging lymph nodes in the neck

How papillary thyroid cancer is diagnosed

PTC is often detected after a thyroid nodule is found during a routine examination or incidentally on imaging performed for another medical condition. The diagnostic process focuses on determining whether the nodule is cancerous and, if so, identifying the specific thyroid cancer subtype and whether it has spread beyond the thyroid gland. A comprehensive clinical assessment may include:

• Physical examination – The physician will examine the thyroid gland and nearby lymph nodes for nodules, enlargement and other abnormalities.
• Blood tests – Thyroid function tests measure hormone levels to help evaluate overall thyroid function, although many patients with PTC have normal thyroid hormone levels.
• Neck ultrasound – High-resolution ultrasound imaging can help characterize thyroid nodules, evaluate nearby lymph nodes and map areas of possible lymph node involvement before treatment.
• Fine-needle aspiration (FNA) biopsy – Using ultrasound guidance, the physician will remove a small sample of cells from a thyroid nodule for microscopic examination by a pathologist to determine whether cancer is present.
• Molecular testing – If biopsy findings are indeterminate, molecular analysis of the tissue sample may identify genetic alterations that help clarify the diagnosis and guide treatment decisions.
• Computed tomography (CT) or magnetic resonance imaging (MRI) scan – Imaging studies may be recommended if there is concern that the tumor has grown beyond the thyroid or involves nearby structures.
• Radioactive iodine scan – In selected situations, this specialized study may help identify remaining thyroid tissue or detect persistent or recurrent thyroid cancer after treatment.

How papillary thyroid cancer is staged

PTC is staged according to the American Joint Committee on Cancer (AJCC) TNM system, which considers the size of the primary tumor, nearby lymph node involvement and whether the cancer has spread to distant parts of the body (metastasis). Thyroid cancer stages generally range from 1 through 4, with stage 4 representing the most advanced disease. 

Thyroid cancer is unique in that the patient’s age plays a major role in the staging process. In patients younger than 55, papillary thyroid cancer is classified as stage 1 unless it has spread to distant parts of the body, in which case it is classified as stage 2.

For patients 55 and older, staging depends on the size of the primary tumor, whether it has grown beyond the thyroid, whether nearby lymph nodes are involved and whether the cancer has spread to distant organs. In general:

• Stage 1 – The cancer is confined to the thyroid or has only limited spread.
• Stage 2 – The cancer may have grown beyond the thyroid or spread to nearby lymph nodes, depending on the extent of disease and other staging factors.
• Stages 3 and 4 – More advanced cancers have spread extensively into nearby structures or to distant organs.

How papillary thyroid cancer is treated

Treatment for PTC is tailored to the size of the tumor, whether it has spread beyond the thyroid, the cancer’s molecular characteristics and the patient’s overall health. Typically, a multispecialty team of head and neck surgeons, endocrinologists, medical oncologists, radiation oncologists, radiologists and pathologists will collaboratively develop an individualized treatment plan. Options may include:

• Surgery – Surgical treatment may involve the removal of one thyroid lobe (lobectomy) or the entire thyroid gland (total thyroidectomy). Affected lymph nodes may also be removed if lymph node involvement is suspected or confirmed.
• Radioactive iodine (RAI) therapy – After surgery, RAI may be recommended for select patients to destroy remaining thyroid tissue or microscopic cancer cells while minimizing radiation exposure to the rest of the body.
• Thyroid hormone therapy – Patients who undergo a total thyroidectomy require lifelong thyroid hormone replacement. In some cases, thyroid hormone medication is also used after treatment to suppress thyroid-stimulating hormone (TSH), which may help reduce the risk of recurrence.
• Targeted therapy – For advanced or recurrent PTC with specific genetic alterations, such as BRAF or RET changes, targeted medications may help slow tumor growth when surgery or radioactive iodine is no longer effective.
• External beam radiation therapy (EBRT) – Although not routinely used for most patients with PTC, EBRT may be considered if the tumor cannot be completely removed surgically or the cancer recurs in the neck.
• Chemotherapy – Traditional chemotherapy is rarely used for papillary thyroid cancer but may be considered in select cases when other treatment options are not appropriate.
• Clinical trials – Through participation in a carefully controlled research study, eligible patients may have access to innovative therapies, including targeted therapies, immunotherapies and other emerging treatment approaches for advanced thyroid cancer.

The Moffitt Cancer Center difference for papillary thyroid cancer

At Moffitt, patients with PTC can receive comprehensive care from a multispecialty team experienced in diagnosing and treating both common and complex thyroid tumors. The specialists in our Thyroid Clinic work together to develop individualized treatment plans using advanced imaging, molecular testing and evidence-based therapies while preserving healthy thyroid tissue whenever appropriate.

As a National Cancer Institute (NCI)-designated Comprehensive Cancer Center, Moffitt also provides eligible patients with access to a robust portfolio of clinical trials designed to evaluate the effectiveness of promising new treatment strategies for thyroid cancer.

If you would like to learn more about papillary thyroid cancer, you can request an appointment with a specialist at Moffitt by calling 1-888-663-3488 or submitting a new patient registration form online. Patients in Florida can also request a virtual visit appointment. We do not require referrals.