PET-CT Accuracy in Diagnosing Gastric Cancer

The accuracy rate of PET-CT scans in detecting gastric cancer ranges between 80% and 90%. However, the gold standard for diagnosing stomach cancer remains pathological biopsy performed during endoscopy. PET-CT is generally not used as the primary diagnostic tool for gastric cancer, but it plays a significant role in certain clinical scenarios.

Assessing Distant Metastasis

One of the key uses of PET-CT in gastric cancer management is identifying distant metastases. It can detect whether the cancer has spread to areas such as the lungs, peritoneal cavity, or liver. When conventional imaging methods like standard CT or MRI fail to provide a clear diagnosis, PET-CT can offer more definitive insights into the presence of metastatic disease in other parts of the body.

Evaluating Treatment Response

Another major benefit of PET-CT is its ability to assess how well a patient is responding to treatment. A baseline PET-CT scan can be performed before therapy begins. After undergoing treatments such as chemotherapy, immunotherapy, or targeted therapy, a follow-up PET-CT scan can be conducted. A decrease in radiotracer uptake typically indicates a positive response to treatment, helping clinicians determine the effectiveness of the chosen therapeutic approach.

Despite its advantages, PET-CT has limitations in diagnosing certain types of gastric cancer. For instance, poorly differentiated cancers such as signet ring cell carcinoma and low-grade adenocarcinoma often do not take up the radiotracer effectively, which significantly reduces the diagnostic value of PET-CT in these cases.

In summary, while PET-CT is a powerful imaging tool with valuable applications in gastric cancer care, it is not universally effective for all subtypes of the disease and should be used in conjunction with other diagnostic methods for the most accurate results.