ROSH Gastrointestinal Practice Exam

Which initial diagnostic test is most appropriate for staging pancreatic cancer in a patient with weight loss, jaundice, and abdominal pain?

1. Biopsy

2. CA 19-9 antigen

3. CT scan

4. MRI

The correct answer is: CT scan

The initial diagnostic test most appropriate for staging pancreatic cancer is a CT scan. This imaging technique is valuable because it provides detailed cross-sectional images of the abdominal structures, which helps to identify the size of the pancreatic tumor, assess involvement of surrounding vessels, and detect metastasis to other organs. In cases of suspected pancreatic cancer, a CT scan can highlight key features such as the presence of a mass, ductal dilatation, and lymphadenopathy, all crucial for determining the extent of disease and helping guide management decisions. While a biopsy and serum marker CA 19-9 can play important roles in the overall evaluation of a patient with pancreatic cancer, they are typically used after imaging tests have provided an initial assessment. A biopsy provides tissue for histological confirmation but is not the best first step for staging. CA 19-9, although a useful tumor marker that can provide insights into tumor burden and response to treatment, is not definitive for staging on its own and can be influenced by other conditions. MRI is also a useful imaging modality, particularly in certain scenarios, but a CT scan is more commonly used as the first-line imaging tool due to its rapid availability, high specificity, and detailed anatomical visualization for staging purposes.