Gastric cancer

Gastric cancer
Name	Gastric cancer
Field	Oncology, Gastroenterology, Pathology
Symptoms	Weight loss, abdominal pain, dysphagia
Complications	Perforation, bleeding, metastasis
Onset	Middle to late adulthood
Causes	Helicobacter pylori, dietary factors, genetic syndromes
Diagnosis	Endoscopy with biopsy, imaging
Treatment	Surgery, chemotherapy, radiotherapy, targeted therapy, immunotherapy

Gastric cancer is a malignant neoplasm arising in the stomach lining that commonly presents with nonspecific gastrointestinal complaints and systemic manifestations. It is managed across multidisciplinary teams involving surgical oncology, medical oncology, radiation oncology, and pathology, and has variable incidence and outcomes in different regions and populations.

Signs and symptoms

Early presentation often includes vague epigastric discomfort, anorexia, and weight loss noted by clinicians in outpatient settings such as Mayo Clinic or Johns Hopkins Hospital case series; these signs can be mistaken for peptic ulcer disease documented in cohorts from Cleveland Clinic and Mount Sinai Health System. Progressive disease may show dysphagia linked to involvement of the gastroesophageal junction as discussed in publications from Memorial Sloan Kettering Cancer Center and the National Cancer Institute (United States). Advanced features include visible metastases to the liver and peritoneum reported in radiology series at Massachusetts General Hospital and urgent complications such as perforation and hemorrhage requiring care described in surgical texts from Royal College of Surgeons and American College of Surgeons. Paraneoplastic phenomena and cachexia are topics in reviews influenced by research from Karolinska Institutet and Institut Gustave Roussy.

Causes and risk factors

Infection with Helicobacter pylori is established as a major risk factor in epidemiological studies from World Health Organization and International Agency for Research on Cancer reports; dietary nitrosamines and high-salt diets were implicated in case-control studies from Nagasaki University and Seoul National University Hospital. Tobacco use and heavy alcohol consumption have been associated with increased risk in population registries such as Surveillance, Epidemiology, and End Results Program and cohorts from UK Biobank. Hereditary syndromes including hereditary diffuse gastric cancer linked to CDH1 mutations were first described in families followed at University of Cambridge and University of Toronto; other genetic predispositions are examined in consortia like The Cancer Genome Atlas and International Gastric Cancer Linkage Consortium. Prior gastric surgery, chronic atrophic gastritis, and autoimmune gastritis are cited in textbooks from Oxford University Press and clinical guidelines by European Society for Medical Oncology.

Pathology and classification

Histologic classification draws on Lauren's scheme and WHO taxonomy detailed in monographs from World Health Organization (WHO) and reviews from Pathology Outlines; tumors are divided into intestinal and diffuse types in classic pathology described at Mayo Clinic and Johns Hopkins Hospital. Molecular subtyping by The Cancer Genome Atlas network identifies subgroups with distinct genomic alterations highlighted in publications from Dana-Farber Cancer Institute and Harvard Medical School. Staging follows the TNM system maintained by American Joint Committee on Cancer and Union for International Cancer Control, and grading and margins are reported in surgical pathology protocols from College of American Pathologists.

Diagnosis

Definitive diagnosis relies on upper endoscopy with directed biopsy performed by gastroenterologists trained at centers such as Cleveland Clinic and Mount Sinai Health System, with histopathology interpreted using criteria from World Health Organization (WHO). Cross-sectional imaging with CT and PET/CT is guided by radiology protocols from Radiological Society of North America and applied in staging at Memorial Sloan Kettering Cancer Center. Endoscopic ultrasound for locoregional assessment is described in guidelines from American Society for Gastrointestinal Endoscopy and staging laparoscopy is used selectively following algorithms developed at University of California, San Francisco and St. George's Hospital. Biomarker testing for HER2 with methodologies from College of American Pathologists and molecular assays referenced by National Comprehensive Cancer Network inform targeted therapy decisions.

Prevention and screening

Population prevention strategies include Helicobacter pylori eradication programs modeled on interventions in Japan and South Korea and public health campaigns informed by World Health Organization analyses. Dietary modification and smoking cessation initiatives have been promoted through platforms such as Centers for Disease Control and Prevention and Public Health England. Screening programs using endoscopic surveillance are implemented in high-incidence regions like Japan and Korea University Medical Center and debated in health policy literature from NICE and European Commission. Genetic counseling and prophylactic gastrectomy for CDH1 mutation carriers are managed in specialized centers including MD Anderson Cancer Center and Vancouver General Hospital.

Treatment

Curative treatment for localized disease centers on gastrectomy with lymphadenectomy as described in surgical series from Johns Hopkins Hospital and Memorial Sloan Kettering Cancer Center, with approaches varying between D1 and D2 dissections informed by trials from Medical Research Council (United Kingdom) and Dutch Gastric Cancer Group. Perioperative chemotherapy regimens such as FLOT derive from randomized trials conducted by groups including European Organisation for Research and Treatment of Cancer and Gastrointestinal Tumor Study Group. Adjuvant chemoradiotherapy protocols reference trials led by National Cancer Institute (United States) and Asian Cancer Research Group. Targeted therapy for HER2-positive disease uses agents developed through research at Roche and clinical adoption following regulatory decisions by Food and Drug Administration and European Medicines Agency; immunotherapy with PD-1 inhibitors has been evaluated in trials coordinated by CheckMate and KEYNOTE investigators.

Prognosis and epidemiology

Prognosis depends on stage, histology, and molecular features informed by population-based studies from SEER Program and long-term follow-up at tertiary centers like Memorial Sloan Kettering Cancer Center and MD Anderson Cancer Center. Incidence and mortality show geographic variation with high rates in Japan, Korea, and parts of China reported in global burden analyses by Global Burden of Disease Study and World Health Organization data. Survival trends have improved in regions implementing screening and multimodal therapy as documented in national cancer registries such as Cancer Research UK and surveillance reports from Australian Institute of Health and Welfare. Risk stratification tools and prognostic nomograms are developed by consortia including International Gastric Cancer Association and academic groups at Seoul National University Hospital.

Category:Cancer