Clinical outcomes in older adults with advanced thyroid cancer.

Abstract

e18012 Background: Age is a prognostic factor in thyroid cancer, with older adults being at higher risk of aggressive histologic and genomic variants. Despite this, little is known about the benefits and risks of palliative-intent systemic therapy in older adults with advanced thyroid cancer. Methods: We performed a retrospective review of patients ≥ 65 years of age with advanced thyroid cancer referred to medical oncology at our institution for consideration of systemic therapy between 2015 and 2024 ( n = 114). Clinicopathologic, treatment, adverse event, and outcomes data were analyzed. Univariable and multivariable Cox proportional hazards models and Poisson regressions models were used to test for associations between clinicopathological variables and clinical outcomes. The study protocol was approved by the University Health Network Research Ethics Board. Results: 114 patients ≥ 65 years of age were referred to medical oncology for consideration of systemic therapy between 2015 and 2024. The median age was 73 (range 65 – 98) and median Charlson Comorbidity Index (CCI) score (not including points for age and thyroid cancer diagnosis) was 0. Most patients were functionally independent (93%) and had an ECOG performance status of 0 or 1 (88%). 65/114 patients received first-line systemic therapy. Median overall survival (OS) was 4.04 years (95% CI 3.09 – not estimable) in the whole cohort and 3.91 years (95% CI 2.84 – not estimable) in the treated cohort. First-line time-to-treatment discontinuation (TTD) in the treated cohort was 1.59 years (95% CI 0.75 – 4.45). Higher age, male sex, and anaplastic histology predicted shorter OS in the whole cohort. Higher age, male sex, higher CCI, and presence of a BRAF and/or TERT mutation predicted worse OS and/or TTD amongst treated patients. For patients receiving lenvatinib ( n = 37), adverse events led to significant proportions of patients requiring dose reductions (65%), treatment breaks (78%), emergency department (ED) visits (16%), and drug discontinuation (14%). Adverse events led to treatment breaks (56%), ED visits (67%), and drug discontinuation (22%) in patients receiving dabrafenib + trametinib ( n = 9). Geriatric oncology referral, polypharmacy, and presence of a BRAF mutation predicted higher number of ED visits in treated patients. Conclusions: Although survival outcomes were comparable to those described in younger adults, adverse events were common and impactful in older adults. Starting dose optimization and close monitoring based on an individual's risk factors for adverse events and ED visits should be considered. The benefits and risks of treatment must be reflected upon by oncologists with recommendations guided by patient values and preferences.