Diagnostic Approach for Gastric Cancer

Introduction to Diagnostic Guidelines

The European Society for Medical Oncology (ESMO) and other guidelines recommend proceeding directly to upper endoscopy with biopsy as the definitive diagnostic test for gastric cancer, followed by contrast-enhanced CT chest/abdomen/pelvis for staging if malignancy is confirmed 1, 2.
The American College of Radiology (ACR) guidelines make no mention of tumor markers (CEA, CA 19-9, CA 72-4) for initial diagnosis of gastric cancer 1, 2, 3.

The Chinese Society of Clinical Oncology (CSCO) guidelines state that histopathological examination via endoscopic biopsy is the gold standard and mandatory requirement before treatment initiation 2, 4.
The ESMO guidelines recommend that biopsy specimens must be reviewed by an experienced pathologist and reported according to WHO criteria 1, 5.
The National Comprehensive Cancer Network (NCCN) guidelines suggest that the endoscopy should obtain tissue for histological classification and molecular biomarkers, specifically HER2 status 1, 2.

The ESMO guidelines recommend routine blood tests to check for iron-deficiency anemia and assess hepatic/renal function 1, 5, 6.
The ACR guidelines state that contrast-enhanced CT of thorax, abdomen, and pelvis is the primary staging modality 1, 2, 5, 6, 4.
The CSCO guidelines recommend that the CT must use IV contrast with neutral oral contrast (500 mL water) to properly distend the stomach 2, 4.

The ESMO guidelines suggest that endoscopic ultrasound (EUS) is used for accurate T and N staging, with sensitivity of 0.86 and specificity of 0.90 for distinguishing T1/2 from T3/4 tumors 2, 4.
The NCCN guidelines recommend diagnostic laparoscopy with peritoneal washings for all stage IB-III gastric cancers to detect occult peritoneal metastases 1, 5, 6, 4.

The ESMO guidelines state that all gastric or esophagogastric junction adenocarcinomas must undergo HER2 assessment 2, 4.

Upper endoscopy with biopsy is the gold standard diagnostic test for detecting stomach cancer, according to the British Society of Gastroenterology, and remains the investigation of choice for diagnosis 7, 8
The procedure allows direct visualization of suspicious lesions and enables tissue sampling for histopathological confirmation, with a diagnostic yield reaching 100% when six or more samples are obtained 7, 8

Endoscopy can miss gastric cancer in 10% of cases at the first examination, with an additional 10-20% of patients requiring repeat gastroscopy, often due to failure to suspect malignancy or inadequate biopsy sampling 7, 8
Failure to take adequate numbers of biopsies from suspicious areas can lead to missed diagnoses 7, 8

To maximize detection rates, the endoscopist must obtain multiple biopsies from any suspicious lesion, and stopping proton pump inhibitors (PPIs) before the first endoscopy is recommended, as PPIs can mask endoscopic findings and heal malignant ulcers, potentially causing misdiagnosis 7, 8
Photographic documentation of all lesions is necessary 9

Patients over 55 years with new-onset dyspepsia or any patient with alarm features at any age, such as dysphagia, unintentional weight loss, or anemia, should undergo endoscopy 7, 8
Clinical diagnosis is very inaccurate, and endoscopy should be considered even in the absence of alarm features when there is clinical suspicion of malignancy 7, 8