Survival trends in older adults with anaplastic thyroid cancer (ATC): A SEER database study.

Abstract

e18164 Background: ATC is a rare but aggressive type of thyroid cancer, accounting for 1-2% of all thyroid cancers. It is known to be a disease of older adults, with highest incidence in the 7th decade of life. Oncogenic pathways involved in the development of ATC include BRAF, RAS, PI3K, PTEN, TP53 and TERT mutations. Surgery and chemoradiotherapy are the standard treatments. Combined dabrafenib and trametinib was approved by the FDA in 2018 for the treatment of ATC with BRAF V600E mutation. We analyzed the survival outcomes of patients with ATC over the past 20 years and compared survival outcomes before and after 2018. We also assessed if there are any disparities in survival based on demographic factors. Methods: Data was collected from Surveillance, Epidemiology, and End Results (SEER) Research plus data (from 2000 to 2021). Using the ICD code 8021/3, we extracted patients diagnosed with anaplastic carcinoma of thyroid. We included patients older than 65 years at the time of diagnosis. Analysis was stratified based on age, sex, race, stage, median household income and residency. Survival analysis was done with GraphPad Prism. Results: 1283 patients older than 65 years with diagnosis of ATC were noted. 82.75 % were 65-84 years at the time of diagnosis and 17.25% were 85+ years old. 62% were females. 66% of the patients were Caucasians, 13% Hispanics and 7% were blacks. 58% had metastasis at the time of diagnosis, 21% had regional disease and 6% had localized disease. Median overall survival (mOS) was 4 months for the study population. mOS was 2 months in patients older than 85 years at the time of diagnosis, compared to mOS of 4 months for the age group 65-84 (p<0.0001, HR 1.660 95% CI 1.338 to 2.060). mOS was 3 months for those with metastasis, 6 months for regional disease and 9 months for localized disease and(p<0.0001). Among 548 patients with metastatic ATC, 1- and 2-year survival was 10% and 4% respectively. In those who received chemotherapy, the 10-year overall survival was 2.5%. mOS was 4 months for the patients diagnosed before 2018 versus 5 months in 2019-2021 (p=0.0003, HR 1.388 95% CI 1.167 to 1.652). For the years 2000 - 2018, overall, 22% survived for 1 year compared to 32% in 2019–2021. There was no statistical difference in survival outcomes when stratified based on gender, race, marital status, median household income, and residency. Conclusions: Despite introduction of novel targeted therapies, prognosis of ATC continues to be dismal. A marginal benefit was noted for patients diagnosed after 2018. Survival outcomes are worse in adults older than 85 years, and in those who have metastasis at the time of diagnosis. There are no differences in survival outcomes based on demographic factors. Further research is needed for better understanding of tumor genetics especially among the long-term survival patients which might pave the way for new precision therapies to improve survival of ATC in older adults.