Tumor Size Is Still a Useful Prognostic Factor for the Therapeutic Plan of Papillary Thyroid Carcinoma / 대한갑상선학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Papillary thyroid microcarcinoma (PTMC) was regarded as early-stage carcinoma, but its aggressiveness has been frequently reported. We performed this study to compare the clinicopathologic characteristics of PTMC with those of papillary thyroid carcinoma (PTC) >1 cm. We evaluated the association of clinicopathologic parameters of PTMC with tumor size divided by each millimeter. MATERIALS AND METHODS: We retrospectively analyzed the medical records of 1,139 patients with PTMC and 1,296 patients with PTC >1 cm who underwent thyroidectomy from 1995 to 2004 at Samsung Medical Center. The aggressive variants of PTC were excluded in the subjects. RESULTS: Multifocality, extrathyroidal invasion (ETI), lymph node invasion (LNI), and distant metastasis (DM) were significantly less frequent in PTMC than PTC >1 cm (p1 cm (recurrence 2.9% vs. 8.1%, p<0.001; mortality 0.5% vs. 1.5%, p<0.05). Tumor size was correlated with the rates of multifocality, ETI, LNI, and DM in all PTC (p<0.01). All patients with DM had the tumor size 0.6 cm in diameter or more. Among PTMC, the rates of LNI, multifocality, and N1b significantly increased when tumor size exceeded 0.3 cm, 0.4 cm, and 0.6 cm, respectively (p<0.05). CONCLUSION: Recurrence and mortality rates of PTMC were extremely low, although local invasion was detected on the level of subcentimeter. Tumor size was well correlated with the aggressiveness of PTC. We suggest that tumor size is still a useful prognostic factor for the therapeutic plan of PTC.