Can CT Scans Detect Stomach Cancer?

Computed Tomography (CT) scans can detect certain types of stomach cancer, particularly in the advanced stages. However, the tumor typically needs to be of a certain size—usually at least 5mm, and sometimes even larger than 1cm—for it to be clearly visible on a CT scan. Due to its limited sensitivity, CT may not always detect smaller or early-stage tumors.

Endoscopy remains one of the most effective diagnostic tools for stomach cancer. This procedure allows doctors to visually examine the stomach lining and detect abnormalities that may indicate cancer. Unlike CT scans, endoscopy can identify early-stage stomach cancer, including very small lesions—sometimes as small as 1mm, referred to as "point cancer." These tiny lesions can be accurately diagnosed through endoscopic examination.

In addition to detecting cancer, endoscopy provides detailed information about the tumor's location, size, extent, and how deeply it has invaded the stomach wall. During the procedure, a biopsy can be performed, where a small tissue sample is taken and examined under a microscope. This helps determine the exact type of cancer and guides the selection of appropriate chemotherapy treatments. This critical step—pathological analysis—cannot be achieved through CT imaging.

While CT scans are useful for assessing the spread of known cancer and evaluating surrounding organs, they should be considered a complementary tool rather than a primary diagnostic method for stomach cancer. For early and accurate diagnosis, endoscopy with biopsy remains the gold standard.