The popular diabetes drug Victoza (generic: liraglutide) has recently been linked to thyroid cancer, a disease that occurs when abnormal cells begin to grow in the thyroid gland. Consumer watchdog group Public Citizen has filed a petition with the U.S. Food & Drug Administration (FDA) to take Victoza off the market because of the risk of thyroid cancer and other serious side effects. Signs and symptoms of Victoza thyroid cancer include abnormal lumps in the neck, difficulty swallowing or breathing, and frequent cough.
What’s the Problem?
Prior to the FDA’s 2010 approval of Victoza, the administration began to question whether the drug could cause thyroid cancer because clinical studies showed that Byetta, a similar diabetes drug, might. The FDA eventually concluded that Victoza caused the formation of thyroid C-cell tumors in rodents. For this reason, the administration has required that Victoza packaging include a so-called ‘black box warning’ – the strictest such warning allowed by law – informing consumers of the risk of thyroid cancer.
Thyroid Cancer Overview
Thyroid cancer is a disease that originates in the cells of the thyroid – a butterfly-shaped gland located at the base of the neck. The thyroid’s main function is to produce hormones that regulate the heart rate, blood pressure, body temperature and weight. Although the disease is quite rare in the U.S., thyroid cancer rates have increased significantly over the past several years. Many in the medical community believe this is because new technology is allowing them to diagnose mild cases of the disease that would have gone undetected in the past.
Types of Thyroid Cancer
There are four major classifications of thyroid cancer:
- Papillary Carcinoma – By far the most common variety of thyroid cancer, papillary carcinoma usually affects women of childbearing age. It spreads slowly and is the most treatable form of the disease.
- Medullary Carcinoma – Cancer of non-thyroid cells that are normally present in the thyroid gland. Medullary carcinoma tends to run in families, and has been conclusively linked with several types of specific genetic mutations. This type of the disease requires different methods of treatment than other kinds of thyroid cancer.
- Follicular Carcinoma – Having the highest recurrence rate of any type of thyroid cancer, follicular carcinoma accounts for about 10% of all cases. Mortality of the disease is highly related to the degree of vascular invasion.
- Anaplastic Carcinoma (also known as Giant and Spindle Cell Cancer) – By far the most dangerous form of thyroid cancer, anaplastic carcinoma is a rare form of the disease that spreads quickly and does not respond to radioiodine therapy.
According to recently published statistics from the National Cancer Institute, there are approximately 56,000 newly diagnosed cases of thyroid cancer in the United States each year, the vast majority of which are papillary thyroid cancer. Females are more likely to develop the disease than men by a ratio of 3:1, and though it can occur at any age, it is more likely to begin after the age of 30 (with the aggressiveness of the condition increasing with age). In many cases, thyroid cancer is asymptomatic; however, the first sign of the disease is usually a thyroid nodule.
Symptoms of Thyroid Cancer
Thyroid cancer, a disease that has recently been linked to Victoza, can cause a number of characteristic symptoms depending on the stage of the disease and whether it has migrated to other parts of the body. Telltale symptoms of Victoza thyroid cancer may include enlarged lymph nodes, lumps in the neck, breathing / speaking problems, throat pain, and persistent cough.
In many patients, Victoza thyroid cancer does not exhibit any recognizable symptoms in the early stages of the disease. Many cases are found by chance during routine physical examinations. The doctor may feel the area around the front of the neck, and may ask the patient to swallow water as he or she is doing this. This allows for detection of a cancerous tumor in the thyroid gland.
When symptoms of thyroid cancer do present, they may include:
- Lump in the front of the neck
- Enlargement of the thyroid
- Swelling in the neck
- Pain in the front of the neck that may stretch to the ears
- Change in voice or hoarseness
- Breathing problems (the feeling that you are breathing through a straw)
- Cough that does not go away and is not caused by a cold
- Cough with blood
- Swallowing problems
According to the National Cancer Institute, thyroid cancer is rarer than most other forms of the disease, with approximately 56,460 cases diagnosed in 2012. The condition occurs in the thyroid gland, which is located at the bottom of the throat and plays a critical role in the regulation of hormones. Thyroid cancer occurs more often in women, asian people, younger individuals, and patients with a family history of the disease.
There are several varieties of thyroid cancer – the most common type, papillary carcinoma, is also the most treatable, and typically affects females. The most deadly variety, anaplastic carcinoma, is also the least commonly-reported. Follicular carcinoma is the type most likely to recur, and medullary carcinoma (when the non-thyroid cells in the thyroid gland develop cancer) is most likely to be inherited.
How Can Victoza Cause Thyroid Cancer?
Recent studies have determined that Victoza, an FDA-approved type 2 diabetes medication, has the potential to cause thyroid cancer. This rare disease occurs when abnormal cells multiply and form tumors within the thyroid, a gland in the neck that controls how the body uses energy, makes proteins, and controls how sensitive the body is to other hormones. This article discusses theories on how scientists believe Victoza causes thyroid cancer, and the petition to recall the drug submitted by Public Citizen.
Victoza was a controversial drug even before it was approved by the U.S. Food & Drug Administration (FDA). In clearing the drug, the FDA chose to ignore the recommendations of three of its drug safety reviewers. In clinical trials, high doses of Victoza were found to cause thyroid tumors in rats and mice, although the administration said at the time that it was not known if Victoza had the potential to cause thyroid cancer in humans. The clinical safety reviewer noted that at the time of approval, there were already nearly a dozen different medications for type 2 diabetes on the market, so there was little need to approve another drug whose safety profile was questionable.
Despite these serious concerns, FDA’s director of new drugs overruled all other considerations, including the clinical safety reviewers, in clearing Victoza for sale on the U.S. market. However, the FDA did ask drugmaker Novo Nordisk to conduct a five-year study to look at Victoza’s association with thyroid cancer, pancreatic cancer, pancreatitis, low blood sugar levels, and allergic reactions.
What tests are used to diagnose Victoza thyroid cancer?
Victoza thyroid cancer tests and diagnosis procedures may include:
- Biopsy – A biopsy may be performed on suspicious thyroid nodules to look for cancer. This is typically performed with a needle in a procedure called fine needle aspiration (FNA). Some patients will have to undergo a surgical biopsy, where the nodule, or the thyroid gland itself, is taken out.
- Imaging tests – A number of imaging scans may be implemented to look at thyroid nodules for cancer. These include nuclear scans, computed tomography (CT or ‘cat’) scans, magnetic resonance imaging (MRI), or thyroid ultrasounds.
- Blood tests – Although they are unable to diagnose thyroid cancer, blood tests may be used to analyze the thyroid’s activity and to test for hypothyroidism or hyperthyroidism. When medullary thyroid cancer is suspected, doctors may test for elevated levels of calcium, as this can be a sign of the disease. Genetic testing may also be ordered to identify the gene linked to medullary thyroid cancer.
For Victoza users suffering from thyroid cancer, treatments are typically staged to be as effective as possible. In the vast majority of cases, treatment includes surgery, although the type of surgery depends on the patient’s age and tumor size. Some small thyroid cancer tumors can only be cured through surgical intervention.
What Treatments and Drugs are Used to Fight Victoza Thyroid Cancer?
Victoza thyroid cancer treatments and drugs may include:
- Surgery – Two types of surgery may be performed on individuals suffering from thyroid cancer. They include: Partial thyroidectomy (lobectomy), which involves removal of the part of the thyroid gland that has the tumor; and total thyroidectomy, which is the complete removal of the thyroid gland.
- Radioactive iodine therapy – Used to destroy cancerous thyroid tissue that was not extracted during surgery. Radioactive iodine enters the bloodstream, where it travels to the thyroid gland and eliminates any remaining thyroid tissue and cancer cells. Thyroid cells absorb iodine, so the radioactive iodine does not affect any other cells in the body.
- Radiation (External-Beam) Therapy – Most commonly used non-surgical method of treatment for thyroid cancer. The purpose of radiation therapy is to eliminate cancer cells, decrease the size of the tumor, and relieve symptoms using high-energy external beams.
- Chemotherapy – Uses a chemical cocktail to eliminate cancer cells. Unfortunately, chemotherapy kills normal cells as well as cancerous cells. Chemo is a systemic treatment, meaning that the drug(s) are administered by pill orally or injected into a vein, and circulate throughout the patient’s entire body. In some cases, chemotherapy is used in combination with external-beam radiation therapy.
- Whole body thyroid scan – Depending on the stage and location of the disease, a whole body thyroid scan may be ordered to assist in measuring therapy progress. Whole body thyroid scans are able to determine whether the cancer has migrated to other parts of the patient’s body.
- Complementary and alternative treatments – A number of non-traditional, alternative therapies can work wonders in making the patient feel better and have a more positive outlook. Many patients have found musical or artistic self-expression of great use in combatting the symptoms of thyroid cancer. Visualization, imagery, and mind-body exercises such as those offered by Tai Chi or yoga can be amazingly effective.
Thyroid Cancer Complications
For Victoza users who develop thyroid cancer, complications can occur even after the gland itself has been removed. The disease has been found to have the ability to return years or even decades after treatment.
Victoza thyroid cancer complications may include:
- Cancer migration – Unfortunately, in many patients, thyroid cancer travels from the thyroid gland to other parts of the body. It has been estimated that upwards of 20% of people who develop thyroid cancer will suffer a recurrence of the disease in other areas of their body (most often in the bones or lungs).
- Lowered calcium levels – If the parathyroid glands are taken out during thyroid cancer surgery, it can result in decreased calcium levels. The parathyroids are located behind the thyroid gland, and produce hormones that regulate calcium levels in the human body.
- Recurrence – Thyroid cancer is a disease that often returns, years or even decades after treatment. It has been estimated that approximately 20% of individuals with thyroid cancer will experience a recurrence of the disease in the neck. Even if the patient has had their thyroid gland surgically removed, the disease can return when cancerous cells migrate to other regions of the body prior to surgery. Thyroid cancer may also recur in tissues left behind during surgery, or in the lymph nodes of the neck.
The following tests may be performed to determine a recurrence of Victoza thyroid cancer:
- Radioactive Iodine Uptake Scan (RAIU) – Procedure where radioactive dye is injected into the patient to help find evidence of cancer.
- Ultrasound scan – Uses high frequency sound waves to examine the thyroid gland for problems.
- Thyroglobulin testing – Test to find thyroglobulin, which should only be present if the patient still has thyroid cancer.
Victoza Side Effects
In addition to having the potential to cause thyroid cancer, Victoza has also been linked to the following serious side effects: