PSA refers to ‘prostate specific antigen’ a protein which is made and secreted by the prostate gland.
PSA is a blood test and used as a screening tool to detect prostate cancer. Since the introduction of PSA test for screening of prostate cancer, there has been a significant decline in mortality from prostate cancer. Prior to PSA screening, over 75% of men diagnosed with prostate cancer already had cancer spread (metastasis), compared to now where less than 5% of patients diagnosed with prostate cancer have metastasis.
However, PSA is not very sensitive nor specific for prostate cancer. Both normal cells as well as cancer cells can secrete PSA and subsequently conditions such as infection of benign enlargement of prostate also can result in elevated levels of PSA. Urologists often use levels of free PSA as well as PSA velocity (rise over time) to improve the diagnostic value of PSA.
Who should have PSA screening?
There are various guidelines regarding PSA screening and it is recommended that clinicians and urologists discuss the pros and cons of screening prior to PSA testing with the patients. Generally PSA should be done once a year for:
– Men aged between 50-70 years of age
– Men aged 40 and above with family history of prostate or breast cancer
– PSA could also be offered in older gentlemen (age >70 years), if they have a life expectancy of over 10 years.
What is the role of MRI in cancer screening?
MRI of prostate has recently been shown to be a valuable tool in diagnosis of prostate cancer; it also provides valuable information regarding spread of cancer beyond prostate, and helps your surgeon to determine involvement of nerves which are essential for maintaining sexual function.
MRI is usually requested by urologists for patients with high index of suspicion for cancer.