BACKGROUND: The detection rates of early gastric cancer (GC) in China are approximately 20%; upon diagnosis, the majority of patients with GC are identified as having advanced stage disease, and in some cases, even metastatic advanced GC. Currently, the optimal treatment strategy for peritoneal metastasis (PM) in GC remains uncertain, and pathological complete response (pCR) is rare following conversion therapy.
METHODS: This case report details the management of a 66-year-old patient diagnosed with advanced stage IVB (T4N2M1c) adenocarcinomas of the gastric cardia with PM who received multimodal therapy comprised of hyperthermic intraperitoneal chemotherapy (HIPEC), XELOX chemotherapy, and anti-programmed cell death-1 (PD-1) therapy followed by radical gastrectomy. Through the multimodal management, the patient attained PCR and experienced long-term survival.
CONCLUSIONS: The conversion therapy protocol combined with HIPEC, XELOX chemotherapy, and anti-PD-1 therapy and our scientific, accurate, full-course management strategy may be propagable for potentially curing patients with advanced GC with PM.

We here present a case report of a patient with Stage IV gastric cancer with peritoneal metastasis (P1, CY1) who underwent conversion surgery after a successful response to chemotherapy (S-1 + oxaliplatin + nivolumab). The patient was a woman in her 60 s. Her chief complaint was epigastric pain. Upper gastrointestinal endoscopy showed Type 4 advanced carcinoma on the lesser curvature of the gastric body. Biopsy showed Group 5 (poorly differentiated adenocarcinoma) and HER2 was negative. Staging laparoscopy revealed seeding in the round ligament of the liver (P1) and adenocarcinoma cells in ascites (CY1). Ten courses of chemotherapy (S-1 + oxaliplatin + nivolumab) were administered, after which contrast-enhanced computed tomography showed that the primary tumor had shrunk and seeding was no longer detectable. Upper gastrointestinal endoscopy revealed scar-like changes. A second staging laparoscopy revealed that ascites cytology was negative and a biopsy of the round ligament of the liver showed no malignant cells (P0, CY0). Conversion surgery comprising laparoscopic total gastrectomy with D2 lymph node dissection and resection of the round ligament of the liver was performed. The postoperative course was uneventful. Histopathological examination of the resected specimen revealed no tumor cells in the gastric mesentery or the round ligament of the liver. The pathological diagnosis was gastric cancer [M, U, L, Less, Ant, Post, type4, T3(SS), N0, M0 (H0, P0, CY0), ypStage IIA]. Adjuvant chemotherapy (S-1) was commenced. The patient is still alive 7 months later with no evidence of recurrence.

BACKGROUND: Situs inversus totalis (SIT) is a rare condition in which the positions of abdominal and thoracic organs present a \"mirror image\" of the normal ones in the median sagittal plane. Although minimally invasive surgery has evolved to achieve laparoscopic gastrectomy for gastric cancer (GC) patients with SIT, it is difficult to perform lymphadenectomy (LND) in such a transposed anatomical condition. Herein, we report the cases of two patients with SIT who successfully underwent laparoscopy-assisted gastrectomy (LAG) with D2 LND.
METHODS: Case 1: A 65-year-old man was admitted for intermittent abdominal pain and distension, occasional belching, and acid reflux for 4 mo. He was diagnosed with GC (cT3N1-2M0) with SIT. Before surgery, he had undergone four cycles of neoadjuvant chemotherapy and immunotherapy. Then, the patient was evaluated as having a partial response, and laparoscopy-assisted distal gastrectomy with D2 LND and Billroth II reconstruction were performed. The operation was performed successfully within 240 min with an estimated blood loss of 50 mL and no severe complications. The patient was discharged on postoperative day (POD) 9. Case 2: A 55-year-old man was admitted for upper abdominal distension with pain and discomfort after eating for 3 mo. He was diagnosed with GC (cT3N1M0) with SIT. He had a history of hypertension for more than 10 years; however, his blood pressure was well-controlled via regular medication. We performed laparoscopy-assisted total gastrectomy with D2 LND and Roux-en-Y reconstruction. The operation was performed successfully within 168 min with an estimated blood loss of 50 mL and no severe complications. The patient was discharged on POD 10.
CONCLUSIONS: LAG with D2 LND could be considered an accessible, safe, and curative procedure for advanced GC patients with SIT.

BACKGROUND: Gastric hamartomatous inverted polyps (GHIPs) are benign polyps of the gastric submucosal layer. Currently there are 52 reported cases in the English literature. According to a literature review, approximately 27% of GHIPs show a coexisting carcinoma.
METHODS: A 66-year-old man was referred to our institution with ulcerative lesions detected on esophagogastroduodenoscopy (EGD) during a regular check-up. Other medical findings were nonspecific. The lesions had borderline histologic features that could not exclude malignancy and were followed up with three EGDs and biopsies at intervals of 3 mo. The latest biopsy was revealed as an adenocarcinoma. A total gastrectomy was performed to remove the tumor. The surgical specimen revealed a 6.9 cm × 4.5 cm sized GHIP with a coexisting 1.6 cm sized well-differentiated adenocarcinoma which extended to the muscularis propria. The malignancy did not originate from the GHIP but showed an overlap.
CONCLUSIONS: A large GHIP, which was unusually presented as an ulcerative lesion, was surgically removed, and was accompanied by advanced gastric cancer. Regular follow-up and thorough examinations of ulcerative lesions with equivocal biopsy have resulted in appropriate diagnosis and treatment. Therefore, aggressive intervention may be beneficial if GHIP is suspected.

The prognosis for patients with advanced gastric cancer (AGC) is poor, with limited treatment options available due to the difficulty of resection. In recent years, chemotherapy and immunotherapy for AGC have shown promising efficacy. However, there is a controversy regarding the surgery of primary tumors and/or metastases in patients with stage IV gastric cancer after systematic therapy. Here, we present a 63-year-old retired female of AGC with supraclavicular metastasis with positive PD-L1 and tumor mutational burden-high (TMB-H). After receiving 8 cycles of capecitabine and oxaliplatin (XELOX) in combination with tislelizumab, the patient achieved complete remission (CR). No evidence of recurrence was identified during follow-up. To the best of our knowledge, this is the first case of AGC with supraclavicular metastasis who achieved CR after treatment with tislelizumab. The mechanism of CR was discussed by genomic and recent clinical studies. The results indicated that programmed death ligand-1 (PD-L1) combined positive score (CPS) ≥5 may serve as a clinical indication and standard for chemo-immune combination therapy. In combination with other similar reports, patients with microsatellite instability-high/defective mismatch repair (MSI-H/dMMR), (TMB-H), and positive PD-L1 had better sensitivity to tislelizumab. The patient recovered successfully except for symptoms of gastrointestinal hemorrhage during treatment, which may be associated with the treatment cycle and age. Immunotherapy with tislelizumab has been well-established in the treatment of malignant melanoma, lung cancer, and clear-cell kidney cancer, but its efficacy and safety for esophageal and gastric cancers remain to be validated. The CR of our patient suggested the prospects of tislelizumab in the immunotherapy of gastric cancer. Additionally, a watch-and-wait (WW) method maybe offered for patients with AGC who achieved complete clinical remission (CCR) after immune combination therapy if the patient was older or in poor physical condition.

UNASSIGNED: Advanced gastric cancer (AGC) is a malignant disease with limited therapeutic options and a poor prognosis. Recently, immune checkpoint inhibitors (ICIs), represented by inhibitors of programmed cell death 1 (PD-1)/programmed death-ligand 1 (PD-L1), have emerged as a potential gastric cancer (GC) therapy.
UNASSIGNED: This case study aimed to reveal the tumor response to neoadjuvant chemotherapy combined with camrelizumab in a patient with AGC based on the characteristics of the clinical pathology, genomics variation, and gut microbiome. Samples from a 59-year-old male patient diagnosed with locally advanced unresectable GC (cT4bN2M0, high grade) presenting PD-L1-positive, deficient mismatch repair (dMMR), and highly specific gut microbiota enrichment were subjected to target region sequencing, metagenomic sequencing, and immunohistochemistry staining. The patient received neoadjuvant therapy, including camrelizumab, apatinib, S-1, and abraxane, which eventually promoted dramatic tumor shrinkage without serious adverse effects and allowed subsequent radical gastrectomy and lymphadenectomy. Finally, the patient achieved pathologic complete response (pCR), and the recurrence-free survival time was 19 months at the last follow-up in April 2021.
UNASSIGNED: The patient with PD-L1-positive, dMMR, and a highly specific gut microbiota enrichment exhibited a pCR to neoadjuvant chemoimmunotherapy.

BACKGROUND: Situs inversus totalis (SIT) is a relatively rare condition, in which the thoracic and abdominal organs are reversed or mirrored from their normal positions. Here, we reported a case of a patient with SIT and advanced gastric cancer with lymph node metastasis who underwent laparoscopic distal gastrectomy (LDG).
METHODS: A 67-year-old man with SIT was clinically diagnosed with T3N2M0 advanced gastric cancer located in the middle gastric body. Three-dimensional reconstruction of computed tomography angiogram revealed that the common hepatic artery originated from the superior mesenteric artery. The patient underwent LDG with D2 lymph node dissection and Roux-en-Y reconstruction. The postoperative course was uneventful.
CONCLUSIONS: This case report showed that LDG could be safely performed on a patient even under complex conditions, such as advanced gastric cancer with lymph node metastasis with SIT and vascular anomalies.

Metastatic advanced gastric cancer, for which treatment strategies are extremely limited, has a poor prognosis. Complete remission is rare. Patients usually lose the opportunity of therapeutic surgery because the lesions cannot be completely removed, although it can greatly prolong their survival time. Palliative surgery usually suggests bad outcomes. In recent years, the immune checkpoint inhibitor (ICI) nivolumab has shown significant efficacy in the treatment of advanced gastric cancer. However, its applicable conditions and optimal withdrawal time remain controversial owing to its low response rate and high incidence of immune-related adverse events. Herein, we introduce a 66-year-old male patient with advanced gastric cancer with multiple liver metastases who underwent laparoscopic total gastrectomy for acute gastric bleeding. The patient received eight cycles of S-1 plus oxaliplatin (SOX) and switched to eight cycles of SOX plus nivolumab combined regimen in a stable state, later achieving complete remission. There was no recurrence for 32 months after the surgery. This is the first reported case of gastric cancer with multiple liver metastases with long-term complete remission with nivolumab treatment after palliative surgery. The potential mechanism of complete remission was discussed through clinical, genomic, and immune characteristics. The patient had a history of psoriasis and was positive for programmed death ligand 1 (PD-L1), and the interaction of TP53 mutation and HER-2 (-) gene may be associated with complete remission.

Checkpoint inhibitor (CPI) therapy has only recently been introduced in the first-line treatment of advanced gastric cancer. However, later line monotherapy CPI efficacy in a subset of patients was presented about four years prior. Here, we present three cases of advanced gastric adenocarcinoma cancers treated with CPI in early lines years prior to the availability of randomized first line data. All three patients remain in remission without gastrectomy, with the median time from initial diagnosis of approximately 52 months. With long-term follow-up of more than four years, we present a proof of concept that, with early integration of CPI therapy, highly durable responses are possible even in the absence of surgery in patients with advanced gastric and gastroesophageal junction cancers.

Gastric cancer is one of the most common malignant tumors and patients show a short survival, those combined with bone marrow invasion have a median survival of only 37 days. Here we reported the treatment of a 47-year-old male with advanced gastric cancer and complicated with bone marrow invasion and extensive metastases, who did not tolerate chemotherapy, under monotherapy with savolitinib, a MET receptor tyrosine kinase inhibitor. Before treatment, the patient was in severe pain and presented with thrombocytopenia and hemorrhagic anemia. Savolitinib was given based on amplification and rearrangement of the MET gene in his tumor. After savolitinib treatment, the patient\'s condition promptly improved, efficacy evaluation indicated partial remission, and the patient was alive and remained progression-free at 15 weeks at the time of reporting. No obvious adverse reactions occurred. Besides, another case of a female gastric cancer patient with MET amplification who received savolitinib monotherapy as a third-line treatment that remained progression-free at 12 weeks was also reported. This report provides a new reference for understanding MET abnormalities in gastric cancer and offers a possibility for future application of MET tyrosine kinase inhibitors in the therapy of gastric cancer with MET abnormalities. Also, it suggests that sequencing of MET can be considered a routine target in advanced gastric cancer patients.