Evaluation of Etiology, Clinical Manifestations, Diagnosis, Follow-up, Histopathology and Prognosis Factors in Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-analysis

BACKGROUND & OBJECTIVE: The most frequent type of cancer found in the endocrine system is thyroid carcinoma. Among well-differentiated thyroid malignancies, the most commonly occurring type is identified as papillary thyroid carcinoma (PTC), which makes up 70-90% of the cases. A subtype of PTC is papillary thyroid microcarcinoma (PTMC), which includes tumors smaller than 10 mm in diameter. Due to the advancements in diagnostic techniques, the incidence of this type of cancer is on the rise. In this study, we aimed to analyze the factors worsening the PTMC prognosis. METHODS: In the first step, we searched various databases for the factors affecting this tumor. The relevant articles were collected and different outcomes of this tumor and its associated factors which were studied in more than one article, were classified. Finally, we conducted a meta-analysis of these outcomes and their related factors. RESULTS: In the meta-analysis, a significantly association was found between the following factors: recurrence with gender (P<0.001) lymph node metastasis (LNM) (P= 0.003), and extrathyroidal invasion (P<0.001); lymph node metastasis with extrathyroidal invasion (P<0.001), and multifocality (P<0.001); central lymph node metastasis (CLNM) with gender (P=0.001), tumor size (P<0.001), extracapsular invasion (P<0.001), lateral cervical lymph node metastasis (P<0.001), and extrathyroidal invasion (P<0.001); lymph node metastasis resulted in poor outcomes (P<0.001); and finally tumor size with BRAFV600E mutation (P<0.001). CONCLUSION: In conclusion, it is essential to note that greater awareness and understanding of this tumor characteristics and special and separate attention to PTMC can significantly improve the society overall health.