A retrospective study of the clinical features in papillary thyroid microcarcinoma depending on age

The aim of this study was to evaluate the clinical features and correlation of neck lymph node involvement of papillary thyroid microcarcinoma (PTMC) according to patients' age. We divided the patients into three groups according to age: young group (<45 years, n=83), middle group (45-54 years, n=80), and old group (55 years, n=53). The clinical features among the different groups were analyzed retrospectively. All of the 216 patients had received radioiodine ablation at least one time. Among these, 84 patients had central lymph node metastasis (CLNM), 11 patients had lateral lymph node metastasis (LLNM), and 26 patients had both CLNM and LLNM. We show that both lymph node metastasis (LNM) and the CLNM rate were significantly higher in young patients compared with old patients (P=0.000 and 0.000, separately). The radioactive iodine curative ratio in younger patients is also lower than that in the other two groups (37.35, 18.75, and 32.08%, separately, P=0.029). Further Bonferroni test among three groups identified that both LNM and the CLNM rate were significantly higher in the young group than in the old group (P=0.000 and 0.000, separately). Logistic regression analysis showed that young [odds ratio (OR): 2.087, 95% confidence interval (CI): 1.013-4.299, P=0.046] and middle age (OR: 4.049, 95% CI: 1.933-8.482, P=0.000), and extrathyroid extension (OR: 1.952, 95% CI: 1.027-3.711, P=0.041) are independent risk factors for neck LNM. Unlike LNM, young age (<45 years) (OR: 3.667, 95% CI: 1.732-7.761, P=0.001), extrathyroid extension (OR: 2.256, 95% CI: 1.189-4.282, P=0.013), and male sex (OR: 2.057, 95% CI: 1.042-4.061, P=0.038) were found to be independent risk factors for CLNM. However, no independent risk factors were found to be associated with LLNM. The patients with PTMCs had different clinical features according to age. PTMCs in young patients were more aggressive, especially in LNM. Hence, clinicians should consider an individualized treatment according to age in younger patients to achieve better therapeutic efficacy.