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

A prior history of thyroid and non-thyroid malignancies has traditionally been an exclusion criterion in patients with anaplastic thyroid carcinoma (ATC) seeking to enroll in clinical trials. In this study, we examined the impact of prior malignancies on overall survival in patients diagnosed with ATC.In our retrospective cohort study, we identified 451 patients with ATC treated at MD Anderson between 2000-2019. Clinical and pathological information were obtained through chart review. Survival analyses were conducted using Kaplan-Meier method and multivariable Cox proportional hazard models.A history of clinically documented prior differentiated thyroid carcinoma (DTC) was reported in 14% of patients with ATC (n=62), most commonly papillary thyroid carcinoma (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 non-thyroid 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 non-thyroid cancer to ATC diagnosis was 8 years (range: 3 months to 53 years). The most common prior non-thyroid cancers were non-melanoma skin (28.4%), prostate (19.6%), and breast cancer (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 prior non-thyroid cancer. On multivariate analysis after adjusting for age and overall stage, prior DTC, concomitant DTC, and prior non-thyroid cancers all had no significant impact on overall survival.The presence of prior malignancy does not significantly impact overall survival in patients with ATC. Revision of eligibility criteria for enrollment of patients with ATC into clinical trials is warranted.