[Conversion efficacy and safety analysis of PD-1 inhibitor combined with albumin-bound paclitaxel and SOX chemotherapy regimen in initially unresectable advanced gastric cancer].

Résumé

To evaluate the efficacy and safety of a PD-1 inhibitor combined with albumin-bound paclitaxel and the SOX chemotherapy regimen for the conversion therapy of initially unresectable advanced gastric cancer. This study was a prospective cohort study. A total of 112 patients with initially unresectable locally advanced gastric cancer admitted to the Department of General Surgery at the 940th Hospital of the Joint Logistics Support Force of the PLA from January 2021 to December 2024 were enrolled. Inclusion criteria were: (1) age 18-60 years; (2) pathologically confirmed and treatment-naïve status with a single unresectable factor; (3) at least one measurable lesion according to RECIST 1.1 criteria; and (4) an Eastern Cooperative Oncology Group (ECOG) performance status of 0. Exclusion criteria were: (1) presence of massive ascites, or pyloric obstruction; (2) concurrent other malignancies; and (3) severe cardiac, hepatic, or renal dysfunction, or contraindications to the drugs. Patients were divided into a four-drug regimen group (PD-1 inhibitor+albumin-bound paclitaxel+SOX, =48) and three-drug regimen group (PD-1 inhibitor+SOX, =64) according to the treatment regimen. There were no statistically significant differences in baseline characteristics between the four-drug regimen and three-drug regimen groups, including sex, age, tumor location, clinical TNM stage, Borrmann classification, PD-L1 CPS, and MMR status (all >0.05). Observation indicators and evaluation criteria: Primary outcomes were surgical conversion rate, objective response rate (ORR), major pathological response (MPR), and treatment-related adverse events (TRAEs). Efficacy was evaluated using RECIST 1.1 criteria, pathological response using Becker Tumor Regression Grade (TRG), and adverse events using CTCAE 5.0 criteria. (1) Surgical conversion: The surgical conversion rate in the four-drug regimen group was 72.9% (35/48), significantly higher than the 46.9% (30/64) in the three-drug regimen group (7.638, =0.006). (2) Short-term efficacy: The ORR in the four-drug regimen group was 68.8% (33/48), significantly higher than the 43.8% (28/64) in the three-drug regimen group (=6.912, =0.009); the disease three-drug regimen rates (DCR) were 95.8% (46/48) and 84.4% (54/64), respectively, with no significant difference (=3.764, =0.052). (3) Pathological efficacy: Among patients who successfully underwent conversion surgery, the MPR rate was 82.9% (29/35) in the four-drug regimen group and 66.7% (20/30) in the three-drug regimen group, with no significant difference (=2.282,=0.131). (4) Subgroup analysis: In the microsatellite stable (MSS) subgroup, the conversion rate was significantly higher in the four-drug regimen group compared to the three-drug regimen group [71.7% (33/46) vs. 40.0% (22/55), =10.174,