Prognostic indicators in well-differentiated thyroid carcinoma when controlling for stage and treatment

The incidence of thyroid carcinoma is rising. Few studies have examined patient characteristics that influence survival when adjusting for treatment and tumor stage/extent.

Retrospective analysis was performed using the Surveillance Epidemiology and End Results registry data among patients diagnosed with well-differentiated thyroid (WDT) carcinoma during 1988-2009.

Kaplan-Meir survival curves were used to estimate 5- and 10-year cause-specific and overall survival differences by sociodemographics, clinical characteristics, and treatment. Multivariate Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

A total of 83,985 patients were identified with WDT carcinoma. Blacks had higher hazard of death at 5 years (HR, 1.67; 95% CI, 1.42-1.96) and 10 years (HR, 1.57; 95% CI, 1.37-1.80) when compared to Caucasians, but there were no significant differences in cause-specific deaths. Hispanics had higher overall and cause-specific 5-year and 10-year hazard of death (5-year cause-specific: HR, 1.56; 95% CI, 1.23-1.99). Age was the most significant predictor of cause-specific and overall survival, with risk increasing in a nonlinear fashion. After age 45 years, the HR for 5- and 10-year cause-specific survival rose drastically, reaching an HR of 153 for individuals aged 85 years and older (HR, 153.45; 95% CI, 97.84-240.67).

Age was the strongest factor associated with WDT cancer in our study. African Americans had worse overall survival, although only Hispanics had a significantly worse cause-specific survival. These factors should be taken into account in counseling patients and treatment planning.