Endoscopy
Esophagogastroduodenoscopy (EGD) is the main diagnostic tool for gastric cancers. At least 6 to 8 biopsies should be taken from the edges and base of the lesion, because a cancer may be missed if only the surface is sampled.
It is recommended to perform EGD for the evaluation of gastric cancer in:
- patients with new-onset dyspepsia who are older than 55 years
- patients with alarm signs and symptoms who are younger than 55 years
- patients with dyspepsia whose symptoms are not relieved after PPIs and eradication therapy for H. pylori
The alarm signs and symptoms that prompt endoscopy in a younger patient are weight loss, anemia, evident bleeding, dysphagia and recurrent vomiting.
Endoscopic classification of early lesions
A classification system based on endoscopic findings has been developed for assessing early lesion invasion to the submucosal layers and lymph nodes. It classifies the lesions into three types:
- superficial polypoid, type 0-I p and s
- superficial flat or depressed, type 0-II a-c
- superficial excavated, type 0-III
The most common lesion of gastric cancer that has been reported is type 0-IIc, which is superficial depressed.
Serum markers and pepsinogen
There is no specific serum marker for the detection and screening of gastric cancers, but some serum factors are associated with atrophic gastritis and intestinal metaplasia as risk factors for gastric cancer: low pepsinogen I and a low pepsinogen I/pepsinogen II ratio, and hypergastrinemia.
Pepsinogen tests are able to detect less than 1% of cancers, but the useful point about the test is that in more than 90% of the cases it does detect, the cancer is in the early stage. The pepsinogen test is therefore mainly used for the diagnosis of the pre-neoplastic condition of the stomach rather than as a screening test for cancer itself.