The upper endoscopy, also known as esophagogastroduodenoscopy (EGD), is the primary tool for directly examining the lining of the upper digestive tract. This procedure provides physicians with a high-resolution, internal view of the esophagus, stomach, and the initial segment of the small intestine, the duodenum. For individuals suspected of having stomach cancer, the EGD is instrumental in identifying subtle changes or growths that might indicate the presence of malignancy.
Understanding the Upper Endoscopy Procedure
The upper endoscopy visualizes the internal surfaces of the upper gastrointestinal (GI) tract. The patient typically receives a sedative intravenously to promote relaxation and comfort. A numbing spray may also be applied to the throat to suppress the gag reflex as the instrument is passed.
The core instrument is the endoscope, a thin, flexible tube equipped with a miniature camera and a light source at its tip. The physician gently guides this tube through the mouth, down the esophagus, and into the stomach and duodenum. The camera transmits live images to a monitor, allowing for a detailed and close-up inspection of the mucosal lining.
To ensure a clear field of vision, the stomach must be completely empty, which requires the patient to fast for at least six to eight hours before the examination. The physician can also insufflate air through the endoscope to gently expand the stomach walls, flattening the mucosal folds for better visualization. This direct, close-range perspective offers the necessary detail to detect minute surface abnormalities.
Visual Signatures of Stomach Cancer
Endoscopy images reveal distinct visual characteristics that raise suspicion for stomach cancer. Unlike surrounding healthy, pink, and smooth tissue, cancerous lesions often present as irregular, raised, or fungating masses, meaning they have a mushroom-like or protruding appearance. These masses disrupt the normal, uniform contour of the stomach lining.
The color and texture of malignant tissue also tend to differ significantly from benign areas. Suspicious areas may appear pale, grayish, or have an abnormal reddish color known as focal erythema. A particularly telling sign is friability, where the tissue is so fragile that it bleeds easily upon light contact with the endoscope.
Ulcerations associated with cancer typically have irregular, heaped-up, or nodular borders, distinguishing them from the smooth, flat edges of most benign ulcers. High-definition and image-enhanced endoscopy techniques can highlight irregularities in the microvascular and microsurface patterns of the mucosa, which are subtle markers of early cancer. Common sites include the lower section of the stomach, known as the antrum, and the area where the esophagus meets the stomach.
The Role of Biopsy and Staging in Diagnosis
Although the visual findings from the endoscopy image are suggestive, they do not provide a definitive cancer diagnosis. Confirmation requires a biopsy, which involves collecting small tissue samples from the abnormal area through instruments passed directly through the endoscope. For maximum accuracy, multiple biopsies are typically taken from the suspicious lesion.
These collected tissue samples are then sent to a pathology lab for microscopic analysis. Pathologists examine the cells to determine if they are malignant and to classify the specific type of stomach cancer present. This process is necessary because certain benign conditions can visually mimic cancer, and the biopsy provides the definitive evidence.
Once the biopsy confirms the presence of cancer, the next step involves staging, which determines the extent of the disease’s spread. This often requires additional imaging studies beyond the standard EGD, such as Computed Tomography (CT) scans or Positron Emission Tomography (PET) scans. Staging assesses if the cancer has invaded the deeper layers of the stomach wall or spread to nearby lymph nodes and distant organs. Endoscopic ultrasound (EUS) is sometimes used to evaluate how far the tumor has penetrated the stomach wall. This combination provides the complete picture necessary to plan the most effective course of treatment.