Using a nomogram based on preoperative serum fibrinogen levels to predict recurrence of papillary thyroid carcinoma

Background: Hyperfibrinogenemia is increasingly being recognized as an important risk factor related to cancer stage, development and outcomes. We evaluated whether preoperative serum fibrinogen levels predict recurrence of papillary thyroid carcinoma (PTC). Methods: We retrospectively collected data for 1023 PTC patients who underwent surgery at our institution from Aug 2014 to Aug 2016. In total, 414 patients (from Aug 2014 to Dec 2015) were used as the training set to build the model, and 609 patients (from Jan 2016 to Aug 2016) were used as the testing set to validate the model. Results: In the training set, PTC cases with high serum fibrinogen levels were more likely to have multiple PTCs (P = 0.001) and to exhibit surrounding tissue or organ invasion (both P < 0.01). Moreover, PTC patients with higher serum fibrinogen levels were also more likely to have an advanced tumor stage (T, P = 0.001) and distance metastasis (P < 0.001), and these patients had a significantly higher rate of postoperative PTC recurrence (P = 0.002). All of these findings were validated in the testing set. The results of univariate and multivariate analyses indicated that hyperfibrinogenemia was a risk factor for PTC recurrence. The identified risk factors were incorporated into a nomogram and validated using the testing set (C-index = 0.811, 95% CI: 0.762-0.871). Conclusion: PTC cases with hyperfibrinogenemia are more likely to have an advanced TNM stage and have a higher rate of PTC recurrence. Our nomogram could be used to objectively and accurately predict PTC recurrence in a clinical setting.