I Have a Thyroid Nodule, Should I Be Worried About Cancer?

Hi, I’m Dr. Masha Livhits, endocrine surgeon at UCLA Health. Most people find out they have a thyroid nodule either by someone feeling a lump in their neck, or having an imaging study like a CT or MRI of the neck for some other reason and then incidentally discovering that they have a nodule in their thyroid gland. If you’ve been told you have a thyroid nodule, the first question that usually comes to mind is—“Could this be cancer?”

The good news is—thyroid nodules are incredibly common, and most of them are not cancer. In fact, studies have shown that up to half of adults have at least one thyroid nodule if you look carefully with ultrasound. Many people have them and never even know it. They will never cause a problem and don’t require treatment.

So let’s talk about what thyroid nodules are, why they happen, and when we should be concerned.

A thyroid nodule is just a lump or growth within the thyroid gland. Some are solid, some are fluid-filled, and some are a mix. Again, they’re usually discovered either during a physical exam, or incidentally on a scan done for some other purpose.

The vast majority of these nodules are benign, meaning not cancer. But of course, our job is to figure out which ones might be suspicious and need further evaluation.

So, what makes a thyroid nodule more concerning for cancer?

The most important thing is what the nodule looks like on ultrasound. There are specific ultrasound features that can make a thyroid nodule suspicious for malignancy. Ultrasound is safe, has no radiation exposure, is painless, and gives us a detailed picture of your thyroid and the nodule itself. We look at things like:

Whether the nodule is solid or cystic.
Cystic nodules, which are fluid filled, are almost never cancerous.
Solid nodules may have a risk of cancer if they have additional suspicious features, like margins around the nodule that are wavy or irregular.
We also want to evaluate the rest of the thyroid to see if there are additional nodules or any abnormal lymph nodes in the neck.

Based on these ultrasound features, we give the nodule a risk score. This helps us to decide whether the nodule needs a biopsy or just monitoring with repeat ultrasound in 1 year. Most thyroid nodules smaller than 1 cm are very unlikely to cause harm, so we usually monitor rather than perform an immediate biopsy to avoid unnecessary invasive procedures. Larger thyroid nodules that are solid may require biopsy to rule out cancer.

If a biopsy is needed, we usually perform a fine needle aspiration, or FNA. That’s a quick, in-office procedure where we use a tiny needle to collect cells from the nodule. Most of the time, the results come back benign. At UCLA Health, we always collect an additional sample for molecular testing. If the biopsy result is uncertain, we will send this sample off to get more information about the risk of cancer in the nodule. But if the result is suspicious, we will discuss treatment options including surgery. I’d like to mention a common concern that many people have, which is the chance of spreading cancer due to the biopsy procedure. Even if your thyroid nodule is a cancer, a thyroid biopsy does not spread cancer because it uses a very small needle that gently removes a few cells without disturbing the surrounding tissue or creating a path for cancer to travel to other parts of the body.

I would like to conclude by saying that even if your nodule turns out to be a cancer, the most common type—papillary thyroid cancer—is usually very slow-growing and highly treatable. In many cases, we can manage it with surgery alone, and most people go on to live completely normal lives.

But again, most thyroid nodules are not cancer. Many don’t need surgery at all. Some nodules we can just watch over time with repeat ultrasounds, especially if they’re small and not causing symptoms.

So if you’ve recently been told you have a thyroid nodule, I know this can be alarming but there’s a good chance it’s benign. The first step is a neck ultrasound with an experienced endocrinologist, radiologist, or surgeon to assess the risk of cancer and whether you need a biopsy, follow-up imaging, or anything more.