Dr. Debasis Maity

Consultant Uro-Surgeon

Medical Discussion

Prostate Specific Antigen (PSA)

What is serum PSA?

  • Also called y-seminoprotein / HKK3
  • PSA (prostate specific antigen) is a glycoprotein, acts as serine protease / arginine protease.
  • Molecular weight = 33 KD (contain 7% carbohydrate,240 amino acid).
  • Found exclusively in epithelial cell of prostate.
  • Functions: lyse the clot in ejaculate (liquefaction), release of spermatozoa from coagulum of semen.
  • PSA gene (HKK3) located in chromosome no 9
  • Ectopic secretion of PSA seen in: breast CA, nodular breast tissue, breast milk, adrenal & renal CA, female serum.
  • PSA is organ specific not cancer specific.
  • Normal level of serum PSA: 1-4 ng/ml in male (50-80 yrs without prostatic disease)
  • Serum PSA become detectable at puberty with ↑LH & testosterone hormone.
  • In male without BPH - change in PSA = .04ng/ml/year
  • In male with BPH - change in PSA = .07- .27 ng/ml/year (between 60-80 years of age)
  • Ejaculation in male (>50years of age)- increases PSA; so repeat test after 48hrs sexual abstinence is helpful.
  • Pt taking 5α reductase inhibitor but PSA increasing - indicate occult malignancy.
  • 28% male with BPH = PSA value more than 4 ng/ml
  • Statins decrease PSA by decreasing lipid
  • PSA should be multiplied with 2 after 6 months of treatment with Dutasteride, with 2.3 after 2 years, with 2.5 after 7 years.
  • PSAD(PSA density) = serum PSA / Prostate Volume; if ≥ .15,require prostate biopsy ( if PSA = 4-10ng/ml & DRE normal).
  • PSA velocity – if > .75ng/ml/yr in male require prostate biopsy.
  • 20% pt with PSA > 20ng/ml & 75% with PSA > 50ng/ml have lymph node metastasis.
  • NCCN guidelines= bone scan to be done if -
    • PSA > 20ng/ml, or
    • Gleason’s score 8-10, or
    • clinical stage T3/ T4, or
    • clinical symptoms like bone pain,
    • Alkaline phosphatase.
Ask a Question
Copyright © 2015-2020 Dr. Debasis Maity