Development and validation of a nomogram to predict overall survival in patients with redefined anaplastic thyroid carcinoma based on the SEER database.

BACKGROUND: According to the latest classification of thyroid tumors released by the WHO in 2022, primary squamous cell carcinoma of the thyroid (PSCCTh) is classified as anaplastic thyroid carcinoma (ATC). The objective of this study was to determine the differences in characteristics between ATC and PSCCTh and develop a nomogram to predict overall survival patients with the redefined anaplastic thyroid carcinoma (rATC).

METHODS: Patients diagnosed with ATC and PSCCTh between 2000 and 2018 from the Surveillance, Epidemiology, and End Results (SEER) database were enrolled and randomly divided into a training cohort and a validation cohort with a ratio of 7:3. Overall survival (OS) and cancer-specific survival (CSS) was estimated using the Kaplan-Meier method and compared using log-rank tests. The univariate and multivariate Cox proportional hazards regression analyses were used to determine independent prognostic factors of rATC patients. We then developed and validated nomograms to predict the 3-, 6- and 12-month OS of rATC and the results were evaluated by C-index and calibration curves.

RESULTS: After application of the inclusion and exclusion criteria, a total of 1338 ATC and 127 PSCCTh patients were included in the study. Further, OS and CSS of patients with PSCCTh were better than that of patients with ATC. Prognostic factors were not identical for the two cancers. Multivariate Cox model analysis indicated that age, tumor size, metastasis, surgery, radiotherapy, chemotherapy are independent prognostic factors for CSS in patients with ATC; while for patients with PSCCTh, the corresponding factors are age, and surgery. We selected six survival predictors (age, tumor size, metastasis, surgery, radiation, and, chemotherapy) for nomogram construction. The C-indexes in the training and validation cohort were 0.740 and 0.778, respectively, reflecting the good discrimination ability of the model. The calibration curves also showed good consistency in the probability of 3-, 6-, and 12-month OS between the actual observation and the nomogram prediction.

CONCLUSION: We constructed a nomogram to provide a convenient and reliable tool for predicting OS in rATC patients. Prognostic factors influencing CSS were not identical in patients with ATC and PSCCTh. These findings indicate that different clinical treatment and management plans are required for patients with these two types of thyroid cancer.