Survival of aggressive variants of papillary thyroid carcinoma in patients under 55 years old: a SEER population-based retrospective analysis.

BACKGROUND

Patients younger than 55 years of age with papillary thyroid carcinoma (PTC) have excellent survival. Diffuse sclerosing variant (DSV) and tall cell variant (TCV) of PTC are associated with aggressiveness; the survival of patients <55 years of age with these variants is still unclear. We aim to investigate the clinicopathological features and survival of these variants in the age group <55 years.

METHODS

All adult patients (<55 years old) with DSV, TCV and conventional PTC (CPTC) came from the Surveillance, Epidemiology, and End Results program (1988-2013). Kaplan-Meier method and log-rank test were used to analyze the survival. Prognostic factors associated with survival were analyzed by Cox multivariate regression.

RESULTS

There were 280 DSV, 615 TCV, and 56287 CPTC in the age group <55 years. DSV and TCV were associated with multifocality, extrathyroidal extension, lymph node and distant metastasis (all p < 0.05). The 10-year disease-specific survival (DSS) of TCV was worse than CPTC (96.3 vs. 99.4%, p < 0.01), but there was no significant difference between DSV and CPTC (99.5 vs. 99.4%, p > 0.05). Cox multivariate regression showed TCV was the independent predictor of DSS (HR: 5.39, p < 0.01).

CONCLUSION

In the age group <55 years, DSV and TCV are more likely to exhibit aggressive characteristics than CPTC. Patient <55 years of age with DSV have excellent survival likewise, while patients <55 years of age with TCV carry worse survival. Further investigation for the recurrence risk of patients <55 years with these variants would contribute to optimal clinical management making.