Papillary thyroid carcinoma is the most common of all thyroid cancers (80-85%). It is the most benign of thyroid cancers. It is 3 times more common in women than men. It is a cancer that occurs on average around 50 years of age.
Papillary thyroid carcinoma arises from the epithelial cells of the thyroid follicles. It is in the form of an irregular, sometimes cystic, solid mass. Invades nearby tissues and lymphatics. In 10% of patients, metastasis develops at the first diagnosis. The prognosis is good in cases diagnosed at an early age and early.
Papillary thyroid carcinoma is thought to be associated with radiation exposure. It is more common in people who receive too much radiation to the head or neck region, especially during childhood. However, the susceptibility to radiation exposure can turn into cancer after a waiting period of up to 30 years. Exposure to radiation due to environmental conditions also increases the possibility of papillary thyroid carcinoma.
Familial and genetic causes have been identified in 5% of papillary thyroid carcinomas. Especially diseases such as familial adenomatous polyposis-Gardner syndrome, Werner syndrome and Carney complex type 1 pose a risk for papillary thyroid carcinoma.
Papillary thyroid carcinoma develops as a painless mass in the thyroid gland.
Diagnosis of papillary thyroid carcinoma:
Papillary thyroid carcinoma patients are mostly patients without thyroid hormone abnormalities. There may be no abnormality in the thyroid hormone profile. In patients suspected by thyroid ultrasonography, a definitive diagnosis is made with fine needle aspiration biopsy.
Irregular blood supply and hypoechoic areas are characteristic on thyroid ultrasonography. The borders of the thyroid gland are irregular. Sometimes microcalcifications can be seen and microcalcifications are specific for this cancer. Nodules or nodules may be seen in the thyroid gland.
In patients diagnosed with papillary thyroid carcinoma, advanced imaging methods such as CT, MRI and PET/CT can be applied to evaluate the level of development and spread of the cancer.
Treatment of papillary thyroid carcinoma:
After diagnosis and staging of papillary thyroid carcinoma, the most effective treatment is surgery. Preoperative risk assessment is performed and surgical treatment is applied in appropriate patients. Surgical treatment may be in the form of lobectomy or total thyroidectomy. Which one should be applied is decided together with the patient’s clinic, the size and extent of the tumor, the patient’s risks for surgical treatment, and the stage of the tumor.
Radioactive iodine treatment can be applied to clean the remaining thyroid tissues after surgical treatment. Radioactive iodine treatment is decided according to the size of the tumor and whether there is distant metastasis. Radioactive iodine therapy also has its own risks and possible complications. Chemotherapy can be applied to clear the remaining thyroid tissues.
The most common agents used in papillary thyroid carcinoma chemotherapy are:
- Anti-angiogenic multitargeted kinase inhibitors (aaMKI-lenvatinib, sorafenib)
- BRAF kinase inhibitors (vemurafenib, dabrafenib)
- MEK inhibitors (trametinib, cobimetinib)
- They are kinase inhibitors (larotrectinib) that target different pathways such as NTR
- RET inhibitors (selpercatinib).
Since thyroid hormones will decrease after surgical treatment, patients will need to receive lifelong thyroid replacement therapy. However, exceptionally, papillary thyroid carcinoma cells remaining in the tissue can proliferate again under the influence of TSH. For this reason, drug therapy is started with a sufficient dose of T4 hormone replacement to suppress TSH secretion.
In the treatment of papillary thyroid carcinoma, ablation trials with thermal ablation or radiofrequency ultrasonography can also be performed.
Although papillary thyroid carcinoma has a good prognosis, it may have a worse prognosis in advanced age patients, men, when there is cancer beyond the thyroid, in patients with large tumor size, in those with remarkable tissue blood supply and differentiation, and in more aggressively progressive subtypes.
After surgical treatment, patients should be re-evaluated every 6 months for 5 years and examined for recurrence.