Clinical staging is based on all of the following except...?

• A. physical examination
• B. tumor tissue
• C. laboratory findings
• D. imaging studies

Answer: (B)

Clinical staging relies on what can be assessed without removing tissue: a careful physical examination to feel for masses or signs of spread, imaging studies such as CT, MRI, or PET to visualize the tumor and metastases, and laboratory findings that reflect disease impact on organs or tumor activity. The actual tumor tissue, obtained by biopsy or surgery, provides histologic details and the pathologic assessment of invasion and nodal involvement, which are used for pathologic staging rather than clinical staging. So tumor tissue is not part of clinical staging, making it the exception.