Tumorigenesis is now considered to be the result of a complex, multistep, multigenetic alteration. First, there is abnormal cell proliferation, manifested by uncontrolled cell division, at which stage the cells still have a normal appearance; then, the structure and function of the cells are affected and normal physiology is lost; and finally, as genetic mutations accumulate, the cells become completely malignant. These mutated cells cause damage to neighboring cells and organs, and even distant organs (distant metastasis).
This last stage is called “malignancy” and the preceding process of proliferation and structural abnormalities is called “precancerous lesion”, which is equivalent to the “early warning” stage before cancer.
Does thyroid cancer have a “precancerous” stage?
Does thyroid cancer have a “precancerous” stage?
There is no definite precancerous stage for papillary and follicular thyroid cancer. Some rare genetic syndromes are associated with them, such as familial adenomatous polyposis (FAP), which may be combined with papillary carcinoma, and multiple hamartoma syndrome (also known as Cowden’s disease), which may be combined with follicular carcinoma.
Medullary thyroid carcinoma has a well-defined precancerous lesion called “neoplastic parafollicular hyperplasia”, which microscopically appears as an increase in the number of parafollicular cells and abnormal changes in cell structure. Currently, the majority of “tumorigenic parafollicular hyperplasia” is found in patients with familial myeloid carcinoma. The diagnosis of this condition is difficult to confirm by conventional pathology. To confirm the diagnosis, additional genetic testing is needed to look for mutations in the RET gene that are common in familial myeloid carcinoma.
However, this precancerous lesion is not very valuable in practice. This is because once a case of familial medullary carcinoma is diagnosed, physicians genetically test the entire family. Early surgical intervention is usually recommended for family members who carry the RET mutation and do not develop the disease.
Benign nodules are not “precancerous”
.
With the exception of tumorigenic parafollicular hyperplasia, there is no recognized precancerous lesion in thyroid cancer. The current medical community does not consider benign thyroid nodules to be an “early warning” stage before the onset of thyroid cancer. The most important thing to do is to follow up with your doctor regularly.
Co-written by Dr. Jiaqian Hu, Cancer Hospital of Fudan University