Paradoxes in thyroid carcinoma treatment: analysis of the SEER database 2010-2013

Abstract

Thyroid cancer is a common malignant disease with high survival rate (98.1%, 2006-2012, Surveillance Epidemiology and End Results (SEER) program). In this study, we investigated the treatment paradoxes in thyroid T0 and micro-carcinoma patients. 48,234 thyroid carcinoma patients were identified from 2010 to 2013 in SEER*Stat database (version 8.2.1) released in 2016. Survival analysis showed a significantly lower thyroid carcinoma-specific survival in T0 patients compared with T1-T3 patients. In propensity score analysis, T0 patients had a similar survival curve with T1-T3 patients when lymph node and distant metastasis stages were matched. When all variables, including radiation and surgery treatment, were matched, T0 patients had significantly higher survival compared to T3 patients. These findings suggested that more metastasis and less treatment led to poorer prognosis in T0 patients. Another paradox is about thyroid micro-carcinoma. The survival rate of micro-carcinoma patients was high (4 years survival rate was 99.92%), and more than 99% micro-carcinoma patients received surgery. Interestingly, all the patients who died because of thyroid carcinoma received surgery. Survival analysis showed no difference in survival when patients stratified by surgery or radiation. In conclusion, we suggested paradoxes in thyroid carcinoma treatment: over-treated in micro-carcinoma patients and less-treated in T0 patients.

Keywords: cox regression model; epidemiology and end results (SEER) database; propensity score; surgery and radiation treatment; thyroid carcinoma.

Figure 1. Kaplan Meier curves among patients stratified by T-stage for all cause mortality (A, B: Log rank test p < 0.0001) and thyroid carcinoma-specific mortality (C, D: Log rank test p < 0.0001)

Figure 2. Kaplan Meier curves for matched T-stage pairs

Age, race and differentiation grade matching between T0 and T1 (A), T0 and T2 (D), T0 and T3 (G), T0 and T4 (J). Age, race, differentiation grade, N / M stage matched between T0 and T1 (B), T0 and T2 (E), T0 and T3 (H), T0 and T4 (K). Age, race, differentiation grade, N / M stage, surgery and radiation treatment matched between T0 and T1 (C), T0 and T2 (F), T0 and T3 (I), T0 and T4 (L).

Figure 3. Kaplan Meier curves among thyroid micro-carcinoma patients for thyroid carcinoma specific mortality and thyroid carcinoma-specific mortality stratified by surgery treatment (A Log rank test p = 0.82) and radiation treatment (B Log rank test p = 0.96)