The Gustave Roussy Immune score is a powerful biomarker for predicting therapeutic resistance to chemotherapy in gastric cancer patients

It is highly important to be able to predict the therapeutic efficacy of chemotherapy on patients with unresectable advanced or recurrent gastric cancer (GC). The Gustave Roussy Immune Score (GRIm-s) is a predictor of therapeutic sensitivity to chemotherapy and immune checkpoint inhibitors (ICIs) in other cancers. The present study aimed to analyze the association of the GRIm-s with the therapeutic sensitivity of first-line chemotherapy in GC patients.

We included 156 patients receiving primary chemotherapy treatment for unresectable or advanced recurrent GC between January 2012 and December 2021 at our institution. We evaluated the correlation between the GRIm-s and therapeutic sensitivities to chemotherapy. The GRIm-s was assessed before the start of first-line chemotherapy.

Among the 156 patients, 138 (88.5%) and 18 (11.5%) were classified in the low- and high-risk groups, respectively. The GRIm-s high-risk group was significantly older (p = 0.013), had more advanced unresectable cancer (p = 0.0098), and was significantly less likely to progress to second-line chemotherapy (p = 0.014). The overall survival rate (OS) (p = 0.039) and the progression free survival rate (PFS) (p = 0.017) were significantly worse in the GRIm-s high-risk group. The high GRIm-s was an independent prognostic factor for poor survival in multivariate analysis (p = 0.0094).

Focusing on the GRIm-s before first-line chemotherapy initiation for unresectable advanced or postoperative recurrent GC was useful in predicting the therapeutic resistance to chemotherapy, transition to second-line chemotherapy, and poor prognosis.