Alkaline phophatase (sometimes called “alk phos” for short) is an enzyme produced naturally within the body. Everyone produces a baseline amount of this enzyme regardless of their state of health, gender, or age.
Certain tissues within the body produce alkaline phosphatase in higher amounts than others. The bones and liver are two parts of the body that can make a great deal of alkaline phosphatase.
Alkaline phosphatase can be measured easily with a simple blood test.
What Does Alkaline Phosphatase Have to Do With Prostate Cancer?
Prostate cancer, when it spreads beyond the prostate, shows a strong affinity for the bones. The bones of the pelvis and spine are some of the most common areas of prostate cancer spread.
When prostate cancer or another cancer moves to the bones, the bony tissue in the cancerous areas breaks down and releases increased levels of alkaline phosphatase into the bloodstream.
Measuring the alkaline phosphatase in the blood is, therefore, a way for doctors to have a better idea as to whether prostate cancer has spread to the bones.
A Couple Things to Remember About Alkaline Phosphatase
- An elevated level of alkaline phosphatase does not necessarily mean that there is cancer that has spread to the bones. There are numerous other causes of a high alkaline phosphatase, but in a man already diagnosed with prostate cancer, a rising alkaline phosphatase is a worrisome sign.
- A high alkaline phosphatase cannot tell your doctor that your prostate cancer has definitely spread to the bones. Bone scans, CT scans, and other diagnostic tests are needed for this.
Kumar: Robbins and Cotran: Pathologic Basis of Disease, 7th ed. 2005.