Another annual physical examination season has arrived, and many people find the words “thyroid nodule” written in the ultrasound examination section of their report…
What does this mean? Is it serious? Does it require treatment? These are the first reactions of many people.
Similarly, some friends’ reports will be more specific, stating “nodule in the left lobe of the thyroid, TI-RADS level 3”. What does this mean? It’s hard not to be confused.
Don’t worry, let me explain slowly.
How common are thyroid nodules? What is the probability of malignancy?
The thyroid is a butterfly-shaped organ located in the lower middle part of the neck, primarily responsible for producing thyroid hormones and participating in the regulation of the body’s normal metabolism. The common term “big neck disease” usually refers to chronic enlargement of the thyroid.
Thyroid and Nodule
Thyroid nodules are actually quite common in adults, statistics show that about 50% to 60% of people will have them, which means almost half of the people around us will have thyroid nodules sooner or later, and this proportion increases with age. At the same time, women are also more likely to have such conditions than men.
So, here comes the key point, how harmful are these frequently occurring thyroid nodules to the human body?
That’s right, what everyone is most worried about is whether this nodule has the possibility of being malignant, that is, the probability of thyroid cancer. Statistical data tells us that only about 5% of all thyroid nodules are ultimately proven to be malignant.
Don’t breathe a sigh of relief just yet, although 5% may seem low, for a malignant tumor, even a 1% chance is worth being vigilant, not to mention the overall incidence of thyroid cancer in the general population is only 7.6/100,000, which is a difference of more than six hundred times.
Therefore, when a thyroid nodule is found, determining its benign or malignant nature, or the likelihood of being malignant, becomes an important issue for every patient and doctor.
How to determine the benign or malignant nature of thyroid nodules?
Modern medicine has developed for hundreds of years, but the gold standard for the diagnosis of malignant tumors has not changed – pathology. That is to say, we need to remove a part of the tissue specimen for testing, and only under the microscope can we finally determine the nature of these nodules.
Specific to thyroid nodules, it means that a biopsy for pathology is needed. Regardless of the considerable cost of the examination, the biopsy itself is an invasive procedure that causes pain and bleeding, so for patients, this decision is not easy to make.
So, what is the solution? The solution is to stratify the risks for patients. Well, in layman’s terms, there should be a set of screening criteria for patients, striving to neither miss a malignant nodule nor falsely kill a benign nodule. That is, to improve the positive rate of biopsy, to make a diagnosis with each one, while those who do not have biopsy also do not have missed or misdiagnoses.
This goal is not easy to achieve. In the past, the common practice was that since missing the diagnosis of malignant tumors has serious consequences, well, as long as nodules are found, I will take a biopsy, so that thyroid cancer cannot slip through the net.
The principle is sound, but the cost is also high, countless benign nodules that are wrongly killed are “unclosed”… In fact, even today, for various reasons, some medical institutions still follow this practice, performing biopsies regardless of the likelihood of the nodule being benign or malignant, and even directly operating.
Now, ultrasound scanning, as the most commonly used method for thyroid examination, is convenient, fast, radiation-free, and non-invasive, and naturally people have high hopes for it, hoping to determine the nature of nodules through the imaging performance of ultrasound scanning. After years of research, people have indeed formed some consensuses, and nodules with the following manifestations suggest a high possibility of malignant tumors:
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Hypoechoic nodules;
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Punctate microcalcification;
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No peripheral halo sign;
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Solid components;
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Irregular or lobulated margins;
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Abundant internal blood flow signals within the nodule;
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Larger than 2cm;
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A ratio of anteroposterior to transverse diameter greater than 1.
But please note, here it only suggests the possibility of malignant tumors, and there is no single standard that can accurately tell us that this is a malignant tumor. Moreover, some of the above descriptions are still somewhat vague and subjective, and different ultrasound doctors may give quite different reports for the same nodule.
So, if you really show the report to the doctor and ask, “Do I need a biopsy?” It is not uncommon for 10 doctors to give 3 to 4 different answers… The academic term for this is “inter-observer bias”.
TI-RADS System
Knock on the blackboard, the key point is coming.
In 2009, scholars proposed a standardized system to quantitatively evaluate the degree of benign and malignant thyroid nodules, which later became the famous TI-RADS system (Thyroid Imaging-Reporting and Data System).
In this system, every ultrasound imaging performance that may be related to the benign and malignant nature of the nodule (such as those listed above) is given different scores and summed up to obtain the final grading. After relatively sufficient research, people have also concluded the probability of malignancy corresponding to each grade of nodules, as well as the corresponding recommended treatment strategies (see the table below).
Thyroid Nodule TI-RADS Grading and Treatment Recommendations (ACR 2017 Edition)
With this system, doctors can more objectively and consistently analyze and judge a thyroid nodule, and there will no longer be an embarrassing situation where different doctors have different treatment suggestions for the same nodule, leaving patients at a loss.
Unfortunately, although this system has been recognized by the international mainstream academic community and has been published for about ten years, some domestic institutions have not yet adopted it in their routine physical examination reports. Many institutions still use traditional narrative descriptions to report thyroid nodules, which brings trouble to the doctors who interpret the results, making it difficult to tell patients more accurately and quantitatively the probability of benign and malignant nature of the nodule (still using vague descriptions like possible, probably).
So, if your physical examination report mentions thyroid nodules but does not clearly report the TI-RADS grading, then strictly speaking, this is a less standardized report, and it is best to go to a qualified institution to have a thyroid ultrasound scan redone.
Thank you for patiently reading this far. If you find all the above too dry and difficult to understand, just remember the following points:
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Thyroid nodules are very common, and more than half of adults will have them; -
Most thyroid nodules are benign and do not require any treatment (of course, they are also unlikely to regress on their own); -
Further examination is needed for nodules with suspicious ultrasound findings; -
Check if your report mentions TI-RADS grading, if so, refer to the table above; if not, it is best to re-examine and consult a doctor for a complete assessment.
