Establishment and validation of a nomogram for estimating the overall survival of vulvar squamous cell carcinoma patients aged 50 years or older

Abstract

This study aimed to develop a nomogram for estimating the overall survival (OS) of vulvar squamous cell carcinoma patients aged ≥50 years based on their clinicopathological characteristics. The Surveillance, Epidemiology and End Results (SEER) database was searched for cases diagnosed with vulvar squamous cell carcinoma from 2000 to 2019. They were randomly grouped into a training and a test cohort in a 7:3 ratio. Cox regression analyses were performed to identify risk factors associated with the overall survival rate of the patients. Then, the nomogram was built based on independent factors selected by the minimum Akaike Information Criterion (AIC) value in multivariate Cox regression analyses. The performance of the nomogram was assessed by its concordance index (C-index) and the area under curve (AUC). Its predictive power was determined by calibration plot and clinical applicability by decision curve analysis (DCA). A total of 3048 patients were identified and randomized into the training (n = 2146) and validation (n = 902) cohort. The validation indicated that the nomogram had good recognition ability for clinical trials, patient counseling, and rationalizing therapeutic modalities. The C-index for OS rates was 0.729 (95%Confidence Interval (CI): 0.715–0.743) in the training cohort and 0.717 (95% CI: 0.693–0.741) in the validation cohort. The AUCs of the 1-, 3- and 5-year OS were 0.789, 0.781 and 0.775 in the training cohort and 0.815, 0.772 and 0.748 in the validation cohort. Calibration plots showed that the nomogram had good predictive power, and DCA demonstrated that the proposed nomogram could provide a net clinical benefit. Our nomogram demonstrated promising accuracy in comprehensively predicting the OS of elderly vulvar squamous cell carcinoma patients. It could be used as a reference to guide individualized treatments and plan the follow-up of elderly patients with vulvar squamous cell carcinoma.