Abstract:

Background and purpose: Spindle cell melanoma (SCM) is a rare type of melanoma with few studies on its survival prognosis. The nomogram for predicting 5- and 10-year cancer-specific survival (CSS) and overall survival (OS) of patients with cutaneous SCM was constructed and validated by extracting SCM clinical information from a public database. Methods: A total of 1 445 patients were screened from the Surveillance, Epidemiology, and End Results (SEER) database and divided into training cohort (n=1 011) and validation cohort (n=434). The nomogram was constructed based on these independent prognostic factors which were determined by univariate and multivariate COX regression analyses. The concordance index (C-index), receiver operating characteristic (ROC) curve and calibration curve were used to evaluate the discrimination and accuracy of the nomogram. Decision curve analysis (DCA) was used to evaluate the clinical utility of the model. Results: Age, tumor site, thickness, ulceration, N stage, M stage and surgery were included in the prediction model. The C-index of the nomogram was 0.778 (CSS) and 0.753 (OS) in the training cohort, and 0.749 (CSS) and 0.712 (OS) in the validation cohort, respectively. The area under curve (AUC) of 5- and 10-year CSS were 0.815 and the AUC of 5- and 10-year OS were 0.825, and the AUC of 5- and 10-year OS were 0.803 and 0.825 in the training cohort, respectively. The AUC of 5- and 10-year were 0.777 and 0.836, and 0.754 and 0.799 in the validation cohort, respectively. The calibration curve fitted well with the 45° line. DCA showed that the nomogram had the clinical net benefit in a wide range of threshold probabilities and had good clinical application value. Conclusion: The nomogram had good predictive ability and clinical application value for the prognosis of SCM patients.

Key words: Spindle cell melanoma, Nomogram, Cancer-specific survival, Overall survival, Prognosis