Victoza (liraglutide) has been linked to an increased risk of thyroid cancer, specifically papillary thyroid cancer and medullary thyroid cancer. When you used Victoza to treat Type-2 Diabetes, you may have been unaware of these risks. Did you develop thyroid cancer after taking Victoza? If so, you are not alone. Recently, a public advocacy group has called for Victoza to be banned, because the risks of using this medication outweigh its benefits.
Victoza (liraglutide) is a once-daily injectable medication that helps adults with Type-2 Diabetes control their blood sugar (glucose) levels, along with diet and exercise. It is manufactured and sold by the drug company Novo Nordisk, and it was approved by the U.S. Food and Drug Administration (FDA) in 2010 (against the recommendation of three FDA scientists). It works by mimicking the hormone GLP-1, which tells the pancreas to produce more insulin. When a diabetic person injects Victoza after a meal, it helps their body produce extra insulin, which helps maintain a normal blood sugar levels.
Since 2010, the use of Victoza has risen dramatically, despite the fact that there are already 11 classes of drugs available to treat Type-2 Diabetes, and these other drugs have long and proven safety records. Compared to these other drugs, Victoza has been linked to a higher risk of thyroid cancer, acute pancreatitis, renal failure, and other severe side effects.
With nearly a dozen diabetes drugs already on the market, why should diabetics choose Victoza? According to the consumer advocacy group Public Citizen, they shouldn’t. The group has recently called for Victoza to be banned in the U.S.
Victoza and Thyroid Cancer
Before Victoza was approved by the FDA, the manufacturers were required to conduct pre-approval safety studies of Victoza in diabetic rodents. They found that Victoza caused malignant tumors of the thyroid gland. The results were most striking at high doses, but an increased risk of thyroid cancer was also seen at normal exposures. This is a warning sign that Victoza could potentially cause thyroid cancer in humans. In response, the FDA required Novo Nordisk to send a letter to doctors specifically warning about the risk of thyroid cancer associated with Victoza. The manufacturer is also required to keep track of all cases of thyroid cancer over the next 15 years.
In human studies, the risk of thyroid cancer was higher for patients taking Victoza than patients who were taking other diabetes drugs:
- Papillary Thyroid Cancer was 3-times more common in Victoza patients
- Thyroid C-cell hyperplasia (proliferation of C-cells in the thyroid) was 2.4-times more common in Victoza patients
Because thyroid cancer is relatively rare, and cancer usually takes several years to develop, the studies are not large enough or long enough to completely estimate the risk of Victoza thyroid cancer. They are a warning sign. Experts will not have a clear picture until more people use Victoza, develop cancer, report their disease, and researchers compile this data and publish studies.
What is Thyroid Cancer?
Thyroid Cancer is a cancer of the thyroid gland, which is located inside the front of the lower neck. This gland is part of the endocrine system, and it secretes hormones that regulates body functions. Some types of thyroid cancer are extremely aggressive and difficult to treat. Most types, however, are relatively easy to control because they do not grow quickly and are usually detected early.
Types of Victoza thyroid cancer may include:
- Papillary thyroid cancer, which is the most common type of thyroid cancer. Fortunately, it is the least dangerous type of thyroid cancer, because it tends to spread slowly. During clinical trials of Victoza, there were 6 cases of papillary thyroid cancer in patients treated with Victoza, compared to 1 case in patients treated with another diabetes drug
- Medullary thyroid cancer, a rare type of thyroid cancer that originates from C-cells (cells that produce the hormone calcitonin). Because medullary thyroid cancer can be detected in blood tests, the first symptom of this cancer may be elevated levels of calcitonin in the bloodstream. This type of thyroid cancer can be deadly when it spreads to other parts of the body.
Symptoms of Victoza Thyroid Cancer
Victoza thyroid cancer does not always have symptoms, which can make it difficult to detect and diagnose. When there are symptoms, these may include:
- A lump that can be felt or seen on the neck
- Difficulty swallowing
- Enlargement of the thyroid gland
- Hoarseness or changing voice
- Neck swelling
- Thyroid lump (nodule)
- Swollen lymph nodes
- Pain in the throat / neck