Background: Gestational trophoblastic neoplasia (GTN) is a rare tumor with an excellent prognosis. This study aimed to refine the FIGO risk score by incorporating immune nutritional factors. Methods: A retrospective analysis was conducted on women diagnosed with GTN between 2005 and 2019 who received chemotherapy (CT). Statistical tests (Wilcoxon, univariate, multivariate analyses) were used to assess associations with response to CT, and Cox regression models were applied to identify factors influencing overall survival (OS). immune nutritional FIGO (in-FIGO) risk score was calculated using significant variables and compared to the original FIGO score using ROC curves. Results: A total of 160 GTN patients were included. There was a positive association between CR and prognostic nutritional index (PNI) (p <0.0001) and neutrophils lymphocyte ratio (NLR) (p <0.001). In multivariate analysis, only PNI had a significant association (p= 0.001). A significant association was found between higher PNI (HR 0.95-IC 0.91-0.99, p= 0.019) and OS. ROC curves of the in-FIGO risk and FIGO risk scores were compared. For CR to chemotherapy, the in-FIGO score had higher sensitivity (71.6 vs. 61.5%), specificity (74.3 vs. 62.9%), and AUC (0.719 vs. 0.633) than the original FIGO score. For OS, the in-FIGO score demonstrated higher sensitivity (92% vs. 72.4%) but lower specificity (45.0% vs. 61.8%) and AUC (0.691 vs. 0.710) compared to the original FIGO score. Conclusions: PNI is a significant predictor of both CR and OS in women with GTN receiving CT. The in-FIGO score demonstrated improved sensitivity and specificity in predicting complete response to CT compared to the original FIGO score.