Stage II differentiated thyroid cancer: A mixed bag

AJCC-TNM Stage II well-differentiated thyroid cancer (WDTC) comprises T2N0M0 tumors in patients ≥45 years of age or metastatic WDTC in patients younger than 45 years. The objectives of this study were to assess the oncological outcome of stage II WDTC and to compare the oncological outcome of metastatic WDTC in patient younger (stage II) and older (stage IVC) than 45 years.

This study involved review of clinical presentation and oncological outcome of population cohort of 2,128 consecutive WDTC, diagnosed during 1970-2010 that includes 215 Stage II WDTC and 61 metastatic WDTC. Cox proportional hazard model was used to assess independent impact of prognostic factors on disease-specific survival (DSS) and disease-free survival (DFS) as calculated by Kaplan-Meier method.

Metastatic and non-metastatic stage II WDTC had a 15-year DSS of 41.7% and 96.7%, respectively (P < 0.001). Multivariable analysis showed a 52 times higher risk of death in metastatic stage II WDTC and the DSS of metastatic stage II WDTC was not statistically different from that of stage IVC WDTC.

Metastatic stage II WDTC is very different from non-metastatic stage II WDTC with oncological outcome similar to stage IVC WDTC.