Prior Thyroid and Nonthyroid Cancer History Do Not Significantly Alter Overall Survival in Patients Diagnosed with Anaplastic Thyroid Cancer

Background: A history of thyroid and nonthyroid malignancies has traditionally been an exclusion criterion in patients with anaplastic thyroid cancer (ATC) seeking to enroll in clinical trials. In this study, we examined the impact of prior malignancies on overall survival (OS) in patients diagnosed with ATC. Methods: In our retrospective cohort study, we identified 451 patients with ATC treated at MD Anderson between 2000 and 2019. Clinical and pathological information was obtained through chart review. Survival analyses were conducted using the Kaplan-Meier method and multivariable Cox proportional hazard models. Results: A history of clinically documented differentiated thyroid cancer (DTC) was reported in 14% of patients with ATC (n = 62), most commonly papillary thyroid cancer (81%, n = 50). The median time from diagnosis of prior DTC to ATC diagnosis was 3.5 years (range: 6 months to 35 years). Concomitant DTC was found on pathology in a higher proportion of patients (52%, n = 234). A history of nonthyroid cancer was reported in 23% of patients (n = 102), where 19% (n = 87) had one, 2% (n = 10) had two, and 1% (n = 5) had three prior cancers. The median time from diagnosis of prior nonthyroid cancer to ATC diagnosis was 8 years (range: 3 months to 53 years). The most common prior nonthyroid cancers were nonmelanoma skin (28.4%), prostate (19.6%), and breast cancers (16.7%). In a subgroup analysis performed in patients with available tumor mutation information (n = 183), the frequency of detected tumor driver mutations (BRAF, RAS, TP53) was not significantly different between patients with ATC with and without a history of nonthyroid cancer. On multivariate analysis after adjusting for age and overall stage, prior DTC, concomitant DTC, and prior nonthyroid cancers, all had no significant impact on OS. Conclusions: The presence of prior malignancy does not significantly impact OS in patients with ATC. Revision of eligibility criteria for enrollment of patients with ATC into clinical trials is warranted.