Aggressiveness and outcome of papillary thyroid carcinoma (PTC) versus microcarcinoma (PMC): A mono-institutional experience

Background: Papillary thyroid carcinoma (PTC) represents 70%-75% of well-differentiated thyroid cancers. Although most reports have shown that papillary thyroid microcarcinomas (PMC) follow an indolent course, a few series have demonstrated that a significant number of them are associated with extrathyroidal extension and nodal or distant metastases. Methods: Four hundred eighty-four patients with papillary thyroid cancer (102, PMC; 382, PTC) were enrolled in this study. The median follow-up was 102 months. Results: No difference between PTC and PMC patients was observed for age, gender, multifocality, extrathyroidal extension, and lymph nodes metastasis. The prevalence of nodal involvement developing during the follow-up period was significantly higher in PMC than PTC (58.8% vs. 38.5%, P=0.002). An unfavorable clinical course occurred in 96 subjects (21.8%). Logistic analysis showed that the strongest association with the worst prognosis was found for age and TNM stage III (P < 0.001). Analysis also confirmed that the presence of intranodular vascularity is a predictor of unfavorable outcome (P = 0.044). Conclusions: We suggest always performing a total thyroidectomy followed by radiometabolic therapy in papillary carcinomas independent of their size. If the choice in PMCs should be more conservative (hemithyroidectomy), we purpose to limit this procedure to the cancers without Doppler features suggesting intranodular vascular pattern.