Objective To explore the effect of sex on the incidence of immune-related cutaneous adverse event (ircAE) during immunotherapy for gastric cancer, and to further analyze the correlation between sex, ircAE and prognosis.

Methods A retrospective analysis was conducted on patients with advanced gastric cancer who received immune checkpoint inhibitors at the Department of Oncology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Medical School, Nanjing University, from February 1, 2022, to December 31, 2024. Clinicopathological characteristics, occurrence of ircAE, and survival data were collected. The incidence of ircAE was compared between male and female patients. Kaplan-Meier method was used to plot survival curves, and univariate Cox regression analysis was performed to assess prognositc factors.

Results A total of 116 patients with advanced gastric cancer were enrolled, including 76 males (65.5%) and 40 females (34.5%). The overall incidence of ircAE was 23.28%, with a higher incidence in male patients than in female patients (28.95% vs 12.50%, P＝0.046). Kaplan-Meier survival analysis on 86 patients with complete follow-up data indicated that patients with ircAE had longer overall survival (OS) than those without ircAE (P＝0.045). Univariate Cox regression analysis showed that male (HR＝0.43, 95%CI 0.22–0.83, P＝0.012) was associated with prolonged OS.

Conclusions In gastric cancer immunotherapy, male patients are more likely to develop ircAE and have longer OS than female patients, and the occurrence of ircAE may be related to prolonged OS.