Characterised by multiple growths in the thyroid gland, multinodular Goitre (MNG) is typically benign but carries a small cancer risk. Factors like family history and nodule features influence cancer risk, necessitating timely imaging and, blood investigations among others. In this second part of the series, ARCHANA JYOTI speaks with the team of AIIMS Delhi’s Surgical Discplines Department headed by Dr Sunil Chumber to get more insight into this

Understanding the Risks and Complications of Cancer in MNG

Are All Nodules Dangerous?

Not all thyroid nodules are harmful. In fact, most nodules in a multinodular goitre are benign, meaning they are not cancerous. However, there is a small chance that some nodules can be malignant (cancerous). Understanding this risk is crucial for proper monitoring and treatment.

Potential Complications of MNG: While MNG itself is usually not life-threatening, it can cause several complications, including:

Compression Symptoms: As the goitre grows, it can press against the windpipe (trachea) and esophagus (food pipe), leading to difficulty breathing and swallowing. This pressure can also cause a noticeable swelling in the neck.

Thyroid Dysfunction: MNG can sometimes lead to hyperthyroidism (overactive thyroid), where the gland produces too much thyroid hormone, causing symptoms like weight loss, rapid heartbeat, and nervousness. Less commonly, it can cause hypothyroidism (underactive thyroid), resulting in fatigue, weight gain, and depression.

Cancer Risk: Although rare, some nodules in a multinodular goitre can become cancerous. Detecting these malignant nodules early is vital for effective treatment.

Recognising Cancer

Risk in MNG

Several factors can increase the risk of thyroid cancer in individuals with MNG:

Family History: A family history of thyroid cancer or genetic conditions that predispose to cancer increases the risk.

Radiation Exposure: Previous exposure to radiation, particularly in childhood, can raise the likelihood of developing thyroid cancer.

Nodule Characteristics: Nodules that are large, rapidly growing, or have certain features seen on ultrasound (such as irregular edges or microcalcifications) may be more suspicious for cancer.

Preventive Measures and Follow-Up

Regular check-ups and appropriate diagnostic tests are crucial for managing the risk of cancer in MNG. If you have a MNG, your doctor may recommend:

• Periodic Ultrasound Exams: To monitor nodule size and characteristics.
• Thyroid Function Tests: To ensure your thyroid is working properly.
• Prompt Biopsy of Suspicious Nodules: Early detection is key to successful treatment.

While the majority of MNG are benign, it is important to be aware of the potential risks and complications, including the small chance of cancer. Regular check-ups, appropriate diagnostic tests, and timely treatment are key to managing this condition effectively. If you have a multinodular goitre or notice any unusual symptoms, consult your doctor  for personalised advice and care. Staying informed and vigilant can help ensure the best possible outcomes.

Blood Investigations

Blood investigations in multinodular goitre form an important part of evaluation. It helps understand the cause of the goitre and the status of thyroid hormone production – increased, normal or decreased. It includes the following:

• TSH (Thyroid Stimulating Hormone) –usually remains normalbut can be reduced in toxic MNG(increased secretion of thyroxine by thyroid gland) and increased if MNG is associated with hypothyroidism (decreased thyroxine secretion)
• Free T4
• Free T3

Both usually remain normal, increased in toxic goitre, can be decreased in goitres with hypothyroidism.

• Serum Tg (thyroglobulin) is usually elevated
• Thyroid autoantibodies – anti-Thyroid Peroxidase (anti-TPO) and anti-Thyroglobulin (anti-Tg) are negative unless some autoimmune activity is present where anti-Tg will be found elevated.

The choice of tests to investigate the functional status of a patient with a simple diffuse goitre or multinodular goitre may differ depending on the geographic areas of the world.

Although serum thyroglobulin correlates with the iodine status and the size of the enlarged thyroid gland, it has little or no value in diagnosis of goitre.

Imaging Modalities

In treating a condition like MNG, doctors often rely on different imaging methods to get a clear picture of what's happening in the thyroid gland. Here's a breakdown of the main ones used:

Ultrasound (US): This is the first imaging investigation to be done in anyone with MNG. It gives a black and white picture of the thyroid gland and allows your doctor to see the size and number of nodules, and even their makeup – whether they're solid, fluid-filled, or a mix of both. Ultrasound images also help identify suspicious features in the nodules that might indicate cancer risk.

Computed Tomography (CT): CT scans provide more detailed images than ultrasound, but is not required for all cases of MNG. Your doctor will ask for this only if required like if the goiter is large, or pressing on other organs, and if cancer is suspected. In these situations, CT scans provide a closer look at the thyroid and nearby structures to help plan treatment.

Magnetic Resonance Imaging (MRI): This is another way to get detailed images of the thyroid and surrounding areas. Again, it is not performed for all patients and has similar indications as for CT scan and is especially useful when doctors suspect the goiter is growing into other tissues, or if a patient is allergic to dye used in CT scans.

Thyroid Scintigraphy: This is a different type of scan in which a special kind of dye  (“radioactive tracer”) is used to take images of the thyroid. It shows if nodules are “hot” or “cold”, which is, whether they are actively working – to produce thyroxine (hot), or not (cold). Hot nodules usually aren't cancerous, but cold ones might need further checking.

Each imaging method has its pros and cons, but your doctor often will use a mix of them to get the full picture of what's going on with the thyroid. This helps them make the best decisions about treatment and keep an eye out for any potential problems.

(To be concluded)