Dear OncoLink "Ask The Experts,"
My mom was diagnosed with metastatic breast cancer to her liver last year. Her oncologist tracks her alkaline phosphatase level monthly, recently the numbers are climbing up, but her AST/ALT are stable. What could this mean?
Kevin R. Fox, MD, Assistant Director, Clinical Affairs and Associate Professor of Hematology/Oncology at the Abramson Cancer Center of the University of Pennsylvania, responds:
Alkaline phosphatase is an enzyme that is produced by the liver as well as the bone. In the setting of stable AST and ALT levels (which are enzymes specific to the liver), the rising alkaline phosphatase is more likely to be of bony origin. Alkaline phosphatase is typically released during periods of bone growth, and can rise and fall erratically with bone activity. If the patient has even a small amount of metastatic breast cancer in the bone, for example, the rising alkaline phosphatase could represent healing activity of the bone lesions.
All in all, the alkaline phosphatase is not specific enough to be relied upon on its own, and so I would recommend concentrating on the scans of the liver to make any assessments, as CAT scans and MRI scans are better for detection of suspicious lesions, and can be more specific than blood tests.