Clinical-pathological Characteristics and Prognostic Factors for Papillary Thyroid Microcarcinoma in the Elderly

Background: The incidence of papillary thyroid microcarcinoma (PTMC) has increased dramatically over the past three decades worldwide. The annual rate of increase in the elderly (≥65) PTMC patients is 1.4 times higher than that in the adult (<65) PTMC patients. The aim of the present study is to identify the clinical-pathological characteristics and prognostic factors in the elderly PTMC patients. Methods: The source population is PTMC patients whose information is available in the Surveillance, Epidemiology and End Results (SEER) database (2004-2013). We analyzed specific selected clinical-pathological parameters and prognostic factors for the PTMC patients who were aged 65 or above (N=4812). Results: Within the elderly group, the male patients, in comparison to the females, had a higher percentage of lymph-node metastases (5.29% vs. 12.27%, P < 0.001), distant metastasis (0.27% vs. 1.07%, P < 0.001), and stage III-IV tumors (9.19% vs. 15.85%, P < 0.001). Moreover, the elderly patients had a lower median cause-specific survival (CSS) compared with the adult patients (P < 0.001). Stage III-IV disease (hazard ratio (HR): 8.064, P < 0.001) was a strong risk factor for PTMC CSS. Being female (HR: 0.440, P = 0.011), total thyroidectomy (HR: 0.057, P = 0.001), and lobectomy (HR: 0.058, P < 0.001) were all strong protectors of PTMC CSS. Conclusion: Thyroidectomy improved CSS of the elderly PTMC patients. Compared with thyroid lobectomy, total thyroidectomy did not increase CSS for the elderly PTMC patients. The elderly PTMC patients who received radio therapy did not experience an increase in CSS.