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Supplementary Material for: Estimating Survival Probabilities of Advanced Gastric Cancer Patients in the Second-Line Setting: The Gastric Life Nomogram

posted on 21.08.2018, 09:12 by Pietrantonio F., Barretta F., Fanotto V., Park S.H., Morano F., Fucà G., Niger M., Prisciandaro M., Silvestris N., Bergamo F., Fornaro L., Bordonaro R., Rimassa L., Santini D., Tomasello G., Antonuzzo L., Noventa S., Avallone A., Leone F., Faloppi L., DiDonato S., deBraud F., Lee J., DeVita F., DiBartolomeo M., Miceli R., Aprile G.
Objective: We built and externally validated a nomogram for predicting the overall survival (OS) probability of advanced gastric cancer patients receiving second-line treatment. Methods: The nomogram was developed on a set of 320 Italian patients and validated on two independent sets (295 Italian and 172 Korean patients). Putative prognostic variables were selected using a random forest model and included in the multivariable Cox model. The nomogram’s performance was evaluated by calibration plot and C index. Results: ECOG performance status, neutrophils to lymphocytes ratio, and peritoneal involvement were selected and included into the multivariable model. The C index was 0.72 (95% CI 0.68–0.75) in the development set, 0.69 (95% CI 0.65–0.73) in the Italian validation set, but only 0.57 (95% CI 0.52–0.62) in the Korean set. While Italian calibrations were quite good, the Korean one was poor. Regarding 6-month OS predictions, calibration was best in both Caucasian cohorts and worst the in Asian one. Conclusions: Our nomogram may be a useful tool to predict 3- or 6-month OS in Caucasian gastric cancer patients eligible for second-line therapy. Based on three easy-to-collect variables, the Gastric Life nomogram may help clinicians improve patient selection for second-line treatments and assist in clinical trial enrollment.