Validation of nomograms for overall survival, cancer-specific survival, and recurrence in carcinoma of the major salivary glands

Abstract

Background

The purpose of this study was to investigate the performance of the Memorial Sloan Kettering Cancer Center salivary carcinoma nomograms predicting overall survival, cancer-specific survival, and recurrence with an external validation dataset.

Methods

The validation dataset comprised 123 patients treated between 2010 and 2015 at our institution. They were evaluated by assessing discrimination (concordance index [C-index]) and calibration (plotting predicted vs actual probabilities for quintiles).

Results

The validation cohort (n = 123) showed some differences to the original cohort (n = 301). The validation cohort had less high-grade cancers (P = .006), less lymphovascular invasion (LVI; P < .001) and shorter follow-up of 19 months versus 45.6 months. Validation showed a C-index of 0.833 (95% confidence interval [CI] 0.758-0.908), 0.807 (95% CI 0.717-0.898), and 0.844 (95% CI 0.768-0.920) for overall survival, cancer-specific survival, and recurrence, respectively.

Conclusion

The 3 salivary gland nomograms performed well using a contemporary validation dataset, despite limitations related to sample size, follow-up, and differences in clinical and pathology characteristics between the original and validation cohorts.

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