A nomogram for predicting survival based on hemoglobin A1c and circulating tumor cells in advanced gastric cancer patients receiving immunotherapy.

[BACKGROUND] Our study aimed to investigate the correlation between hemoglobin A1c (HbA1c), circulating tumor cells (CTCs) and prognosis in advanced gastric cancer (GC) patients who received immunotherapy and explore the potential prognostic predictors to develop a nomogram.

[METHODS] We retrospectively enrolled 259 patients with advanced GC treated at Beijing Friendship Hospital between September 2014 and March 2024. Patients were divided into the immunochemotherapy cohort (ICT) and the chemotherapy (CT) cohort. Survival rate was calculated by Kaplan-Meier survival curve, and the differences were evaluated by log-rank test. The univariate and multivariate Cox proportional hazards regression model was used to identify factors independently associated with survival. A nomogram was developed to estimate 6-, 12-, and 18-month progression-free survival (PFS) probability based on the ICT cohort.

[RESULTS] Patients achieved higher PFS in the ICT cohort than the CT cohort. We focused on the ICT cohort and constructed a nomogram based on the multivariate analysis, including five variables: age, PD-L1 expression, HbA1c, CTCs and CEA*. The concordance index value was 0.82 in the training cohort and 0.75 in the validation cohort. Furthermore, we proved the nomogram was clinically useful and performed better than PD-L1 expression staging system. Notably, we found high HbA1c level but not diabetes mellitus significantly affected the efficacy of ICT.

[CONCLUSION] ICT showed better PFS than CT. In addition, HbA1c and CTCs were novel biomarkers to predict PFS in patients treated with ICT. The nomogram could predict PFS of advanced GC patients receiving ICT with increased accuracy and favorable clinical utility.