Thyroid nodules are lumps that form within the thyroid gland. They are extremely common, with estimates that 50-60% of people will develop a thyroid nodule during their lifetime. The vast majority of thyroid nodules are benign (non-cancerous) but around 5% are malignant (cancerous). It’s important to monitor thyroid nodules over time to check for growth or changes that may indicate cancer.
How can I check if my thyroid nodule is growing?
The main ways to monitor thyroid nodule growth are through physical exams, ultrasound scans, and fine needle aspiration biopsies. Here are the key methods:
- Physical exam: Your doctor will feel for lumps or swelling in your neck area around the thyroid. Comparing exams over time can suggest nodule growth.
- Ultrasound: This imaging test uses sound waves to create pictures of the thyroid gland. It can accurately measure nodule size and compare changes over time.
- Fine needle aspiration (FNA) biopsy: A thin needle is inserted into the nodule to draw out cells that are examined under a microscope. Changes in nodule cells can signal abnormal growth.
Your doctor may use one or a combination of these approaches to track your thyroid nodule size. The frequency of monitoring depends on your individual risk factors, but thyroid exams are commonly repeated around every 6-12 months.
What size change indicates a growing thyroid nodule?
There is no absolute cut-off for what constitutes a significantly growing nodule. But in general, an increase of at least 2mm, or around 20% of nodule diameter, over a 6-12 month period is considered suspicious growth warranting further evaluation. The table below shows some example size increases that could indicate meaningful growth:
| Initial nodule size | Follow up size | Size increase |
|---|---|---|
| 5mm | 7mm | 2mm (40% increase) |
| 15mm | 20mm | 5mm (33% increase) |
| 25mm | 30mm | 5mm (20% increase) |
Nodule growth rates can vary considerably, so it’s critical to consider the full clinical picture including risk factors and nodule appearance on ultrasound when assessing for potentially abnormal changes.
What causes thyroid nodules to grow?
There are several possible causes for thyroid nodule growth:
- Benign hyperplasia: An increase in the number of cells forming the nodule, which enlarges it. This is a common cause of growth in benign nodules.
- Inflammation: Swelling and inflammation from autoimmune conditions like Hashimoto’s thyroiditis can increase nodule size.
- Hemorrhage: Bleeding into the nodule causes rapid enlargement. This often happens in benign nodules.
- Malignancy: Cancerous cells multiplying within a nodule leads to expansion. This is the most serious cause of growth.
Doctors will consider these potential reasons when evaluating changes in your thyroid nodule size over time.
What else may indicate a thyroid nodule is growing?
Aside from direct nodule measurement, there are other signs that may suggest thyroid nodule growth:
- Feeling a lump getting larger during neck exams
- Increasing difficulty swallowing or breathing
- Voice changes like hoarseness
- Visible swelling protruding under the skin of the neck
- New onset neck pain or fullness
You may also experience symptoms like unexplained weight gain or fatigue from thyroid hormone changes caused by a growing nodule. Evaluating any new or worsening signs or symptoms around your neck/thyroid region warrants bringing up to your doctor.
How fast can a thyroid nodule grow?
There is a wide variation in how quickly thyroid nodules enlarge:
- Slow growing: Many benign nodules see gradual expansion over years. Their growth may be imperceptible until compared on exams many months or years apart.
- Moderate growth: Nodules may enlargen at a steady pace, around 1-2 mm per year. This results in a visible but not sudden increase in size.
- Rapid growth: Some nodules grow quickly over days or weeks, especially if they hemorrhage. Cancerous nodules may double in volume in under a year.
With malignancy, fast growth is considered higher risk. However, speed of growth alone isn’t definitive – some cancers enlarge slowly while some benign nodules grow rapidly.
Additional factors impacting thyroid nodule growth rate
- Age – nodules are more likely to grow rapidly in younger people
- Nodule size – smaller nodules often grow faster initially
- Pregnancy – hormonal changes can accelerate growth
- Iodine levels – high iodine exposure is linked to faster growth
Your doctor will interpret nodule growth rate along with multiple clinical factors to assess for potential risks.
When to see a doctor
You should see a doctor promptly if you notice any of the following:
- Feeling a lump or fullness in your neck getting noticeably larger
- Increasing difficulty swallowing, breathing, or voice changes
- New swelling or protrusion in the neck area
- Symptoms like unexplained weight changes, fatigue or hoarseness
Routine monitoring for thyroid nodules through neck exams and ultrasounds on a 6-12 month basis is also recommended. This allows comparison to previous size and evaluation of growth patterns over time.
Contact your doctor right away if you experience pain, pressure or difficulty breathing, as this may indicate an enlarging nodule compressing vital neck structures.
How is a growing thyroid nodule evaluated?
If nodule growth is detected or suspected, your doctor will likely order additional tests to determine the cause and assess for cancer risk. Common evaluations include:
- Repeat ultrasound: Provides updated size measurements and looks at nodule appearance for suspicious features.
- Blood tests: Measures thyroid hormone levels which may be disrupted by a growing nodule.
- Fine needle biopsy: Examines cells under a microscope to check for cancerous changes.
- CT/MRI imaging: Provides enhanced visual detail about the nodule and surrounding neck structures.
Based on test results, your doctor may recommend watchful waiting with ongoing monitoring, biopsy for definitive diagnosis, thyroid surgery for nodule removal, or thyroid suppression treatment to halt further growth.
When is growing thyroid nodule surgery needed?
Surgery may be recommended if testing shows:
- Cancer is present or very likely based on biopsy
- Indeterminate biopsy but high clinical suspicion of malignancy
- Large nodule size (over 4cm) with compressive symptoms
- Ultrasound reveals worrisome features suggestive of cancer
- Significant cosmetic concerns over a visible protruding neck mass
The specific surgery depends on factors like nodule size, location, and cancer risk. Common procedures include:
- Lobectomy – Removal of half the thyroid gland containing the nodule
- Near-total thyroidectomy – Removal of almost all thyroid tissue
- Total thyroidectomy – Removal of the entire thyroid gland
Surgery may be able to cure small thyroid cancers confined to a nodule while helping relieve compressive symptoms from large nodules.
Can I shrink a growing thyroid nodule?
There are some nonsurgical treatment options that may help shrink growing thyroid nodules in select cases:
- Thyroid hormone suppression therapy – High doses of thyroid hormone often slow or stop nodule growth by decreasing TSH stimulation.
- Radioactive iodine (RAI) ablation – Swallowing radioactive iodine destroys overactive nodules and can reduce size.
- Ethanol ablation – Injecting pure alcohol into the nodule disrupts blood supply causing cell death and shrinkage.
- Thermal ablation – Heat or cold thermal energy is applied inside the nodule through a needle probe destroying tissue.
However, these treatments are not recommended for suspected cancer since they may miss malignancy. They are mainly used for benign hyperfunctioning nodules or symptomatic enlargement in those not fit for surgery.
What if my nodule keeps growing despite treatment?
If your thyroid nodule continues to enlarge despite nonsurgical therapies, surgical removal may become necessary. This is especially true if there are signs the nodule is becoming cancerous. Thyroid lobectomy or total thyroidectomy can treat large or progressive nodules not responsive to other measures.
What does nodule growth mean for cancer risk?
In general, faster growing nodules raise greater concern for malignancy. However, cancer risk depends on multiple factors:
- Nodule appearance – irregular, solid, hypoechoic on ultrasound are higher risk features
- Patient demographics – young age and male gender increase cancer odds
- Medical history – radiation exposure or family thyroid cancer boosts risk
- Biopsy results – indeterminate or suspicious findings warrant close monitoring
While most growing nodules are benign, it’s important to evaluate the full clinical picture. Your doctor will guide appropriate cancer screening based on your individual risk profile.
What’s the outlook for a growing thyroid nodule?
The prognosis for a growing thyroid nodule depends greatly on whether it is benign or malignant. Some general outlooks include:
- Benign nodules often continue slow enlargement but are not dangerous. They may require treatment for compressive symptoms.
- Follicular adenomas, a benign tumor type, can grow substantially over years but are not life threatening.
- Well-differentiated thyroid cancers linked to growing nodules have a favorable prognosis with proper treatment.
- Undifferentiated thyroid cancers grow rapidly but luckily are very rare.
Regular monitoring and follow up of thyroid nodules is key, as early detection and management of cancerous changes leads to better outcomes. Your doctor will discuss the specifics of your prognosis based on test results.
Conclusion
Thyroid nodules are extremely common, but it’s important to monitor them for growth which may indicate cancer risk. Physical exams, ultrasounds, and biopsies allow measurement of nodule changes over time. An increase of around 2mm or 20% in diameter warrants further evaluation. Sudden enlargement and new neck symptoms should also prompt medical attention. Testing growing nodules for malignant changes can guide appropriate treatment, whether nonsurgical therapies, thyroid surgery, or continued surveillance. Discuss any thyroid nodule growth with your doctor to determine optimal management for your health.