Thyroid nodules are abnormal growths within the thyroid gland. They may be solid, fluid-filled (cystic), or a combination of both. They are fairly common and are typically found when an imaging test or a physical examination is conducted. Most thyroid nodules will be non-cancerous, although some will have cancerous cells. It's a crucial component of thyroid health to determine which nodules should be checked. Clinician exam, thyroid function tests, and ultrasound are typically the first tests that are done. In cases where a nodule is suspicious, a biopsy called a Fine Needle Aspiration (FNA) may be suggested to obtain a closer look at the nodule. But there are instances when the biopsy results are inconclusive as far as possible distinction of the benignness or malignancy of the nodule is concerned. In these instances, another test of the molecules present in thyroid nodules may also be useful. Dr Nikunj Jain, Co-Founder and Head, Nuclear Medicine, at Molecular Diagnostics and Therapy has specialized experience in the evaluation and management of any thyroid condition. His expertise allows patients to receive the information they need about appropriate nuclear medicine investigations and options for their treatment. What Is Molecular Testing for Thyroid Nodules? A molecular test is a special laboratory procedure that studies the changes in the genes of the cells that are taken from a thyroid lump. Seeks out certain mutations, changes in genes, or changes in levels of gene activity that may be linked to thyroid cancer. This is usually obtained by fine-needle aspiration of the sample. As a complement to microscopy, molecular testing is used to analyse some of the genetic characteristics, rather than inspect the cells' appearance under the microscope. A doctor may use this information to determine the chance of cancer and determine if any closer follow-up or additional tests are needed or if surgery is necessary. When Is Molecular Testing Recommended?
The majority of thyroid nodules do not require molecular testing. It is primarily used when the results of the normal investigations are ambiguous.
1. When FNA Results Are Indeterminate
Molecular testing is often advised, frequently for an indeterminate FNA result. In many reports, the thyroid biopsy is categorized in terms of the Bethesda System. The results of Bethesda categories III and IV are indications of a change not reliably discerned by cytology alone. For these cases, molecular testing might be useful to help the health care provider determine the risk of cancer and determine if surgery is better or if the patient should be monitored.
2. When the Risk of Cancer Is Unclear
Doctors use ultrasound to study characteristics of a nodule, such as its size, shape, edges, and internal texture. Some of the results might indicate a possible thyroid cancer. But sometimes a sonogram and a biopsy can give only an uncertain and provisional response. When clinical data can't make up your mind, molecular testing can provide extra information to assist your clinical decision-making.
3. When Doctors Want to Avoid Unnecessary Surgery
Other thyroid patients with abnormal symptoms or nodules might need surgery to make a diagnosis in order to identify the cause of their problems. But not all patients need surgery. This could give doctors alternative options to consider rather than going for diagnostic surgery immediately. The decision is based on molecular test results, ultrasound findings, risk factors of the patient, and the patient's preferences.
4. When Genetic Changes Need Further Evaluation
Some genetic mutations occur in certain types of thyroid cancer. These changes are used by doctors to help them determine if the condition may be cancerous, and what type. None of the genetic findings should, however, be viewed in isolation and without taking the entire clinical situation into consideration. How Is Molecular Testing Performed? The molecular test is typically done on a sample obtained at the time of FNA biopsy. The sample collected is processed in a special laboratory for investigation. The laboratory may test certain genetic changes, gene expression markers, or a combination of molecular markers. These are then compared to the findings of the ultrasound, the cytology report, and the patient's history. Combined information is used by the doctor to discuss next steps. What Are the Benefits of Molecular Testing?
Molecular testing can be helpful in cases where traditional thyroid screening tests are not helpful. There are many benefits to consider, such as:
Improved risk assessment: Estimates the risk of malignancy in certain nodules.
Additional diagnostic information: If not obtained in routine cytology, there will be genetic information provided.
Treatment planning: Aids in decision-making regarding surgical treatment, additional investigations, or further monitoring.
Fewer unnecessary surgeries: If an encouraging outcome is observed, then selected patients can often not be given surgery to diagnose the condition, thus sparing them from a potentially unnecessary procedure.
Individual medical decisions: Supports clinicians to have this information in mind when making clinical judgements for each patient.
But molecular testing should not replace ultrasound, FNA, or a professional medical evaluation. It is also dependent on what type of test it is applied to and what population. When Is Molecular Testing Not Required?
Molecular testing is usually not recommended for all patients with thyroid nodules. For instance, nodule characteristics during the ultrasound examination, including how they look and behave, and clinical characteristics may influence whether they need only occasional sonographic monitoring or permanent surgical removal. Likewise, there are nodules that, when the slides are examined under the microscope, have highly suspicious cell features (cytology) and thus require more specialized evaluation and a treatment plan to determine if cancer is present instead of molecular testing. Indications should be whether the result of the molecular test is likely to influence the patient's management. Role of Nuclear Medicine in Thyroid Nodule Evaluation Nuclear medicine is also used to help determine the diagnosis of some thyroid problems. Thyroid scintigraphy, also called a "thyroid scan," is a test that checks how active the thyroid is by taking a small dose of a radioactive material. It may be ordered when the level of thyroid-stimulating hormone (TSH) is low to decide if a thyroid nodule is overactive. It will assist doctors in determining the cause of hyperthyroidism and determining some of the treatment options. Additional treatment with radioactive iodine can be used for some thyroid diseases. It's crucial to understand that thyroid scintigraphy and molecular testing are two different tests. A thyroid scan is used to assess the activity of the gland, and molecular testing involves checking for the presence of genes seen in the cells taken. Conclusion Molecular testing can be a valuable tool when thyroid nodule biopsy results are uncertain, particularly in selected Bethesda Category III and IV cases. By examining genetic changes in thyroid cells, it provides additional information that may help doctors assess cancer risk and decide between monitoring, further investigation, or surgery. However, it is not required for every thyroid nodule and cannot replace a complete clinical evaluation. Ultrasound, FNA findings, thyroid function tests, and patient history must all be considered before deciding on the next step. Consulting an experienced specialist like Dr. Nikunj Jain at Molecular Diagnostics and Therapy can help patients understand their thyroid investigations and explore appropriate nuclear medicine options when needed.