Importance of serum amyloid A (SAA) level in monitoring disease activity and response to therapy in patients with prostate cancer.

Serum amyloid A (SAA) and acid phosphatase (AcP) levels were determined in serial serum samples of 35 patients in different stages of dissemination and correlated with activity of carcinoma of the prostate. Up to 500-fold increases in SAA level were detected during active periods of cancer with a decrease towards the normal range in remission, in comparison with a 10-fold increase of AcP. The correlation between these two parameters was highly significant (P less than 0.001), but while SAA shows 100% sensitivity during the active stage, AcP shows only 85% sensitivity. It is suggested that although SAA is not a specific marker for any particular illness, due to its characteristic pattern of change in malignant diseases and its high sensitivity, it represents a useful biochemical parameter for the assessment of the activity of the disease to monitor response to therapy during follow-up.