Clinical features and prognostic factors in papillary thyroid microcarcinoma depends on age.

Purpose: Clinical outcomes of papillary thyroid microcarcinoma (PTMC) vary. In general, age at diagnosis is an independent prognostic factor in conventional papillary thyroid carcinoma. However, it is unclear in patients of PTMC. The purpose of this study was to identify clinicopathologic features and prognostic factors of PTMC according to patients' age.

Methods: Five hundred twenty-seven patients who received thyroid surgery and diagnosed as having PTC between January 2001 and December 2009 were included. The clinical data were retrospectively analyzed.

Results: We divided the patients into two groups; group I who were younger than 45 years, and group II who were 45 years old or older. The mean tumor size and incidences of neck lymph nodes involvement of group I was larger than group II. In group II, however, there were more patients who had multiple cancer foci and were body mass index ≥ 25 kg/m(2). The overall incidence of recurrent disease was 3.2%. The incidence of recurrence was higher in group II (2.0% vs. 4.0%), without a statistical difference. In multivariate analysis, the significant risk factors of recurrence were male gender and multifocality in group I, and lymph node metastasis and multifocality in group II. In particular, the male gender and multifocality showed the highest odds ratio (OR) on each group (OR, 4.721 and 6.177).

Conclusion: The patients with PTMCs had different clinical features and prognostic factors according to age. Hence, clinicians should consider a different strategy for therapy and plan for follow-up according to age.