Toripalimab combined with targeted therapy and chemotherapy achieves pathologic complete response in gastric carcinoma: A case report

BACKGROUND: Neoadjuvant or perioperative chemotherapy combined with surgery can reduce postoperative recurrence and improve the long-term survival rate of patients with locally advanced resectable gastric carcinoma. Nivolumab combined with chemotherapy has been recommended by the National Comprehensive Cancer Network guidelines as a first-line therapy for advanced gastric carcinoma/ adenocarcinoma of the gastroesophageal junction and serves as the basis for immunotherapy combined with chemotherapy to become a neoadjuvant therapy. Herein, we report a case in which pathologic complete response was achieved by neoadjuvant administration of toripalimab, Herceptin, and docetaxel, oxaliplatin, calcium folinate, and fluorouracil (FLOT) chemotherapy followed by surgery for human epidermal growth factor receptor 2 (HER2)- and programmed death-ligand 1 (PD-L1)-positive locally advanced gastric carcinoma. We hope that this case will shed some light on neoadjuvant therapy for gastric carcinoma. CASE SUMMARY: The patient was diagnosed with locally advanced adenocarcinoma of the cardia. Immunohistochemistry of the baseline tissues suggested that the tissues were HER2- (fluorescent in situ hybridization) and PD-L1-positive (combined positive score = 1). The patient underwent surgery following a four-cycle neoadjuvant therapy comprising Herceptin, toripalimab, and FLOT chemotherapy. The postoperative pathological findings showed mild atypical hyperplasia of the local glands with chronic mucosal inflammation (proximal stomach), no clear residual tumor (tumor regression grade 0), no regional lymph node metastasis, and negative upper and lower cut ends. The levels of tumor markers were reduced to normal levels after re-examination. With good postoperative recovery, the four-cycle preoperative chemotherapy was continued at the same dosage as that previously administered. After the treatment, the patient was monitored every 3 mo with a follow-up of 12 mo (4 times). As of February 27, 2022, he was in a good condition without disease progression. The clinical trial registration number is E2019401. CONCLUSION: There are many ongoing studies on neoadjuvant immunotherapy combined with chemotherapy or radiotherapy; however, most of these studies are phase II studies with small cohorts. According to the results of some current studies, these combined regimens have shown promising results in terms of efficacy and safety. However, the clinical efficacy and safety of the neoadjuvant therapies used in these combined regimens need to be confirmed by additional prospective phase III clinical trials, and further exploration of molecular markers for effective populations is required.