Outcomes and Trends of Treatments in High-Risk Differentiated Thyroid Cancer

Abstract

Objectives: To analyze the variant-specific survival benefits and usage patterns of standardized treatment combinations of surgery (S), radioactive iodine ablation (RAI), and thyroid-stimulating hormone suppression therapy (THST) for high-risk differentiated thyroid cancer.

Study design: Retrospective cohort study.

Setting: National Cancer Database.

Methods: The 2004-2017 National Cancer Database was queried for patients receiving definitive surgery for high-risk papillary, follicular, or Hurthle cell thyroid cancer. Cox proportional hazards and Kaplan-Meier analyses assessed for treatment-associated survival.

Results: Of 21,076 cases, 18,214 underwent survival analysis with a mean ± SD age of 50.6 ± 17.1 years (71.3% female). When compared with surgery alone, S + RAI was associated with reduced mortality in papillary (hazard ratio [HR], 0.574; P < .001) and follicular (HR, 0.489; P = .004) thyroid cancer. S + RAI + THST was associated with reduced mortality in papillary (HR, 0.514; P < .001), follicular (HR, 0.602; P = .016), and Hurthle cell (HR, 0.504; P = .021) thyroid cancer. In papillary thyroid cancer, S + RAI (91.3%), S + THST (89.2%), and S + RAI + THST (92.7%) were associated with higher 5-year overall survival rates than surgery (85.4%, all P < .001). Papillary thyroid cancer treatments involving THST were associated with higher 5-year overall survival rates than corresponding regimens without THST (all P < .001). In follicular thyroid cancer, S + RAI (73.9%) and S + RAI + THST (78.7%) were associated with higher 5-year overall survival rates than surgery (65.6%, all P < .05). In Hurthle cell thyroid cancer, S + RAI (66.5%) and S + RAI + THST (73.4%) were associated with higher 5-year overall survival rates than surgery (53.7%, all P < .05). On linear regression, THST usage increased by 77.5% (R² = 0.944, P < .001), while RAI usage declined by 11.3% (R² = 0.320, P = .035).

Conclusions: High-risk differentiated thyroid cancer exhibited varying susceptibilities to different treatment combinations depending on histology, with greatest responses to regimens that included RAI. Physician practices have trended toward decreased RAI and increased THST usage.

Keywords: Hurthle cell; follicular; high risk; papillary; survival; thyroid cancer; treatment.