Prostate cancer

How the diagnosis is made

Diagnosis is made on TRUS guided biopsy with 12 or more cores. What sends the patient to that biopsy is an abnormal DRE and/or a raised PSA: those two are the indications for biopsy.

PSA has to be read carefully. It is organ specific but not disease specific, so a raised value says prostate, not cancer. A PSA above 4 ng/mL is considered abnormal, but prostate cancer can be present at all levels of PSA, so a value inside the normal range does not close the question. And a raised PSA can rise due to infection, so before the biopsy take a history, do a rectal examination, look for any abscess or infection with tenderness, and repeat the PSA later.

A nodule felt on a routine examination goes to biopsy even when the PSA is normal. In a 59 year old man found to have a hard, discrete 1.5-cm nodule on his prostate gland, completely asymptomatic, whose prostate-specific antigen done 3 months ago was normal, whose last rectal examination a year earlier was unremarkable and who denies any family history of prostate cancer, what best establishes the diagnosis is transrectal ultrasound-guided prostate biopsy. Transrectal ultrasound of the prostate without biopsy fails to give a diagnosis. Percutaneous prostate biopsy is image-guided and is usually reserved for men with anal canal stenosis or previous abdominal-perineal resection. Transurethral resection of the prostate is indicated in benign prostatic hypertrophy, not for a posterior prostate mass. And urine cytology is not indicated for the work up of a prostate mass.

Put as a rule with its negative written out beside it: the diagnosis of prostate cancer is based on the histology of tissue obtained on prostate biopsy; prostate cancer cannot be diagnosed on the basis of a prostate-specific antigen result, physical examination, adjunctive laboratory testing, imaging studies, or symptoms. The imaging named is MRI and TRUS, transrectal ultrasound - so the imaging finds and guides, and the histology is what makes the diagnosis.