Background: Papillary thyroid microcarcinoma (PTMC) is an indolent carcinoma. The cumulative incidence of death from patients with PTMC and the nomogram built based on the competing risks model have not been described.
Methods: Patients diagnosed with PTMC were selected from the Surveillance, Epidemiology, and End Results (SEER) program (1983-2015). Cumulative incidence function was utilized to calculate the likelihood of death resulting from thyroid cancer. Gray's test was conducted to examine the difference in the cumulative incidence of death between groups. A proportional subdistribution hazard model was constructed and we further built a nomogram to quantify the likelihood of death using the model. A 10-fold cross-validation procedure was adopted to validate the model.
Results: A total of 46 662 patients diagnosed with PTMC were included. The median follow-up time was 81 months (range, 1 to 407 months). The 5-year, 10-year, and 20-year probabilities of death from thyroid carcinoma were 0.3%, 0.6%, and 1.4%, respectively. The age at diagnosis, sex, tumor extension, and lymph node involvement were related to the cumulative incidence of death. A proportional subdistribution hazard model was developed. The performance of the model was good. A nomogram was built based on the model to predict the likelihood of death in patients with PTMC.
Conclusion: The survival rate of patients with PTMC is excellent. The nomogram constructed based on the well-performed competing risks model is helpful for both patients and clinicians.
Keywords: SEER; competing risk; nomogram; papillary thyroid microcarcinoma.
© 2019 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.