Significant effect of posterior line treatment of HER2 positive advanced gastric cancer: A case report

At present, there are few options for third line and above treatment of advanced gastric cancer and the single drug effect is poor. HER2 positive gastric cancer is an important subtype of gastric cancer and has certain immune characteristics. The combination of HER2 inhibitor and PD-1 inhibitor has a synergistic effect, and anti-tumor drugs targeting HER2 can play an antiangiogenesis role by downregulating VEGF. We report a patient with HER2-positive gastric cancer who developed post-operative tumor recurrence and metastasis after adjuvant chemotherapy and radiotherapy. Trastuzumab combined with albumin paclitaxel was used as secondline treatment with progression-free survival for 9 months. In third line treatment, we retained trastuzumab and combined it with camrelizumab and apatinib. During the treatment period, although the patient stopped taking the drugs due to the side effects of camrelizumab and apatinib, he achieved a PFS of 10.4 months. Considering the good effect of the third line treatment, we added another PD-1 inhibitor and continued to combine trastuzumab treatment. We found that the patient still benefited from the treatment and continued to survive for another 4 months. At present, the patient is treated with DisitamabVedotin (HER2-ADC) combined with PD-1 inhibitor, and no overall survival outcome has been observed.