Lab

LAB

1) Urine analysis to look for hematuria or signs of infection.

2) BUN and Creatinine level to look for ureteral obstruction.

3) PSA is controversial because it lacks specificity to detect prostate cancer, however in combination with a physical exam it is still the best test we have to screen for prostate cancer.

4) voided sample after prostatic massage to look for prostatitis

 

Prostate Specific Antigen – PSA

Role of Screening in Prostate CAncer

Seema Sheth MD Alok Anand MD

The Common Vein Copyright 2010

Introduction

The role of any screening is to provide a cost-effective means of detecting disease with a relatively long so-called dormant phase at a point when it can effectively be treated and change clinical outcomes.

PSA or Prostate Specific Antigen is a 240 amino acid single chain intracellular glycoprotein. It plays a role in liquefying the semen that is formed after ejaculation. It has a half biologic half-life of approximately 2-3 days.

There is considerable debate regarding the role of PSA in screening for prostate cancer.  PSA can be elevated in a variety of situations, including prostate cancer, BPH, and prostatitis. The sensitivity of PSA is about 80%, but the specificity of PSA in detecting prostate cancer is only 65%. In order to improve the sensitivity of PSA in diagnosing prostate cancer, many have utilized PSA velocity, PSA density, and free PSA.

Velocity: Several studies suggest that an increase of PSA greater than 0.75g/year increases the chance of prostate cancer. However, since PSA is highly variable, three separate reading about  months apart from each other are needed.

Density: PSA is increased as the prostate gland enlarges. Therefore, higher PSAs in smaller glands may be a sign of cancer. Some use a cutoff of 0.15g/mL3.

Free PSA: Men with prostate cancer have lower levels of free PSA. if a 25% free PSA cutoff is used, 90% of all prostate cancers can be detected.