Anaplastic thyroid cancer (ATC) is highly aggressive with a poor prognosis. Adjuvant systemic therapy and radiation post-surgery are endorsed by NCCN and ATA guidelines. Our study aimed to identify those at risk of forgoing postoperative adjuvant treatment and to determine survival predictors.

We used the National Cancer Database (NCDB) to identify ATC patients who underwent upfront thyroidectomy from 2010 to 2017, excluding those opting for palliative care. We compared demographics, characteristics, treatments, and outcomes between those who received adjuvant therapy and those who did not. Predictors of receiving adjuvant therapy were identified using logistic regression, while Cox regression identified survival factors.

Of 563 patients, 160 received no adjuvant treatment, 82 received radiation only, 16 received systemic therapy only, and 305 received combination therapy. Notably, over 75 ​% of patients who did not receive adjuvant treatment had it excluded from their treatment plan, not due to refusal. Older age (OR 0.92) and non-white race/ethnicity (OR 0.33) were significant predictors of not receiving adjuvant therapy. Undergoing a total thyroidectomy, an R0 or R1 resection, and radiation or combination therapy were associated with better survival, while non-metropolitan location, primary tumor size >7.5 ​cm, and stage IVC disease were negative factors.

Total thyroidectomy, R0/R1 resection, and adjuvant therapy reduce mortality in ATC patients. However, older patients and minorities are less likely to receive adjuvant therapy, underscoring disparities in treatment adherence.