What is PSA Test?

Prostate-specific antigen is a protein secreted by normal and malignant prostate cells in a man. It acts as a diagnostic marker to detect prostate cancer. However, the PSA is secreted by the non-cancerous and cancerous cells and in conditions like prostatitis and benign prostatic hypertrophy resulting in imprecise results. Despite these factors mentioned above, the PSA test is still considered an important biological marker for the preliminary screening and early detection of prostatic cancer. In most cases, the early stage of the disease does not show any symptoms in men. Prostate cancer is the second most common solid cancer in the world. Therefore, early screening for prostate cancer will prevent morbidity and mortality as prostate cancer often shows symptoms and gets detected in the later stages of the disease.

PSA is a serine protease enzyme produced by the columnar epithelium of prostatic tissue, which enters the blood circulation after secretion. Physiologically, PSA prevents the clumping of seminal fluid and hence helps in impregnation. 

Can PSA tests solely predict prostatic malignancy?

The PSA test is a preliminary screening procedure with a tendency for false-positive and false-negative results. It is also seen in conditions like trauma, infections and benign prostatic hypertrophy(BPH), leading to low specificity. Hence the PSA test is always accompanied by digital rectal examination and Magnetic Resonance Imaging (MRI).

How do you interpret the PSA test?

 The total serum PSA test exists in three different isoforms: intact PSA, pro-PSA, BPH associated PSA.BPH associated PSA is elevated in hypertrophic prostatic tissue. Pro PSA is more commonly seen in aggressive prostate cancer.