Current management of gastric adenocarcinoma: a narrative review
Gastric adenocarcinoma is a leading cause of cancer death worldwide. The management of this aggressive malignancy largely depends on tumor characteristics especially stage. Superficial early-stage gastric cancer can be safely managed by endoscopic resection, though clear negative deep and lateral margins must be obtained. Optimal surgical resection is an essential part of the treatment for locally advanced gastric adenocarcinoma, with perioperative and adjuvant therapies having significant impact on long-term outcomes. Chemoradiation is reserved for patients with suboptimal surgical resection. Recent therapeutic advances have prolonged survival in patients with metastatic gastric adenocarcinoma, include checkpoint inhibitors and biomarker-directed therapy. Targeted therapies in gastric adenocarcinoma include monoclonal antibodies directed against vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-2 (VEGFR-2), and human epidermal growth factor receptor 2 (HER2). While anti-VEGF therapies were not found beneficial in the perioperative setting, the effectiveness of HER2 targeted agents in resectable HER2-positive gastric adenocarcinoma is being studied. Microsatellite instability (MSI) varies greatly in patients with gastric adenocarcinoma between 5-20% based on ethnic origin, tumour heterogeneity and staging. The role chemotherapy in the perioperative setting for patients with MSI-high tumors remains controversial while immunotherapy demonstrates promising results in preliminary studies. Immune checkpoint inhibitors in combination with chemotherapy has been shown to improve outcomes in patients with metastatic gastric adenocarcinoma who express programmed cell death 1 ligand 1 (PD-L1) and is now being investigated in the perioperative setting.
Clinical Outcomes of Endoscopic Submucosal Dissection for Superficial Esophageal Neoplasia in Close Proximity to Esophageal Varices: A Multicenter International Experience
There is limited data on the feasibility of ESD for superficial esophageal neoplasia[SEN] located at or adjacent to esophageal varices [EV]. We aimed to evaluate the outcomes of ESD in these patients. This multicenter, retrospective study included cirrhotic patients with history of EV with SEN, located at or adjacent to EV and underwent ESD. 23 patients with SEN [median lesion size 30mm], 16 squamous cell neoplasia, or 7 Barrett's esophagus related neoplasia were included. Majority were Child Pugh B [56.5%] and had small EV [86%]. En bloc, R0 and curative resection was achieved in 95.6%, 91.3% and 82.6%. Severe intraprocedural bleeding [4.3%] and delayed bleeding [4.3%]were successfully treated endoscopically. No delayed perforation, hepatic decompensation or deaths were observed. During a median follow-up of 36 months[Interquartile range : 22-55], 1 case of local recurrence occurred after non-curative resection. ESD is feasible and effective for SEN located at or adjacent to EV in cirrhotic patients. Albeit, majority of the EV in our study were small in size, when expertise is available, ESD should be considered as a viable option for these patients.
Delayed Surgical Intervention After Chemoradiotherapy in Esophageal Cancer: (DICE) Study
To determine the impact of delayed surgical intervention following chemoradiotherapy (CRT) on survival from esophageal cancer. CRT is a core component of multimodality treatment for locally advanced esophageal cancer. The timing of surgery following CRT may influence the probability of performing an oncological resection and the associated operative morbidity. This was an international, multicenter, cohort study, including patients from 17 centers who received CRT followed by surgery between 2010 and 2020. In the main analysis, patients were divided into 4 groups based upon the interval between CRT and surgery (0-50, 51-100, 101-200, and >200 days) to assess the impact upon 90-day mortality and 5-year overall survival. Multivariable logistic and Cox regression provided hazard ratios (HRs) with 95% CIs adjusted for relevant patient, oncological, and pathologic confounding factors. A total of 2867 patients who underwent esophagectomy after CRT were included. After adjustment for relevant confounders, prolonged interval following CRT was associated with an increased 90-day mortality compared with 0 to 50 days (reference): 51 to 100 days (HR=1.54, 95% CI: 1.04-2.29), 101 to 200 days (HR=2.14, 95% CI: 1.37-3.35), and >200 days (HR=3.06, 95% CI: 1.64-5.69). Similarly, a poorer 5-year overall survival was also observed with prolonged interval following CRT compared with 0 to 50 days (reference): 101 to 200 days (HR=1.41, 95% CI: 1.17-1.70), and >200 days (HR=1.64, 95% CI: 1.24-2.17). Prolonged interval following CRT before esophagectomy is associated with increased 90-day mortality and poorer long-term survival. Further investigation is needed to understand the mechanism that underpins these adverse outcomes observed with a prolonged interval to surgery.
Apposition of Fibroblasts With Metaplastic Gastric Cells Promotes Dysplastic Transition
Elements of field cancerization, including atrophic gastritis, metaplasia, and dysplasia, promote gastric cancer development in association with chronic inflammation. However, it remains unclear how stroma changes during carcinogenesis and how the stroma contributes to progression of gastric preneoplasia. Here we investigated heterogeneity of fibroblasts, one of the most important elements in the stroma, and their roles in neoplastic transformation of metaplasia. We used single-cell transcriptomics to evaluate the cellular heterogeneity of mucosal cells from patients with gastric cancer. Tissue sections from the same cohort and tissue microarrays were used to identify the geographical distribution of distinct fibroblast subsets. We further evaluated the role of fibroblasts from pathologic mucosa in dysplastic progression of metaplastic cells using patient-derived metaplastic gastroids and fibroblasts. We identified 4 subsets of fibroblasts within stromal cells defined by the differential expression of PDGFRA, FBLN2, ACTA2, or PDGFRB. Each subset was distributed distinctively throughout stomach tissues with different proportions at each pathologic stage. The PDGFRα+ subset expanded in metaplasia and cancer compared with normal, maintaining a close proximity with the epithelial compartment. Co-culture of metaplasia- or cancer-derived fibroblasts with gastroids showing the characteristics of spasmolytic polypeptide-expressing metaplasia-induced disordered growth, loss of metaplastic markers, and increases in markers of dysplasia. Culture of metaplastic gastroids with conditioned media from metaplasia- or cancer-derived fibroblasts also promoted dysplastic transition. These findings indicate that fibroblast associations with metaplastic epithelial cells can facilitate direct transition of metaplastic spasmolytic polypeptide-expressing metaplasia cell lineages into dysplastic lineages.
