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Hi! How can I help you today?
Campbell you have ?
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Yes! We have two "Campbell" books in the library:
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Campbell-Walsh-Wein Urology (3-Volume Set) - the landmark urology reference, 87 blocks of content. Speciality: Urology.
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Campbell's Operative Orthopaedics (15th Edition, 2026) - the definitive operative orthopaedics textbook, 46 blocks of content. Speciality: Orthopedics.
Which one are you interested in, and what topic would you like to look up?
urology one
Great choice! Campbell-Walsh-Wein Urology is one of the most comprehensive urology references available.
What topic would you like to look up? For example:
- A specific condition (e.g., BPH, prostate cancer, kidney stones, bladder cancer)
- A procedure (e.g., nephrectomy, cystoscopy, TURP)
- Anatomy or physiology
- Pediatric urology
- Female urology / incontinence
Just let me know what you need!
PSA topic
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Here is a thorough summary of the PSA (Prostate-Specific Antigen) topic from Campbell-Walsh-Wein Urology:
PSA (Prostate-Specific Antigen) - Campbell-Walsh-Wein Urology
What Is PSA?
PSA is also known as hK3 (human kallikrein 3) and is a member of the kallikrein serine protease gene family. The entire family consists of 15 members, all located on the long arm of chromosome 19 (q13.2-q13.4).
Fig. 149.1 - Human kallikrein gene map. PSA is encoded by KLK3, hK2 by KLK2.
Biochemistry & Processing
- PSA is synthesized as a zymogen called pre-pro-PSA (with a 17-amino acid leader sequence)
- Cleavage yields proPSA (inactive, 244 amino acids)
- hK2 cleaves proPSA to produce active PSA
- Active PSA is released from prostatic epithelium into seminal fluid and serum
- In serum, PSA forms complexes with protease inhibitors: α2-macroglobulin (A2M) and α2-antichymotrypsin (ACT)
- hK2 shares 78% amino acid homology with PSA
Molecular Forms of PSA in Serum
| Form | Description | Clinical Significance |
|---|---|---|
| Complexed PSA | Bound to ACT or A2M | Predominant form in cancer |
| Free PSA (fPSA) | Unbound/uncomplexed | Higher in BPH, lower in cancer |
| proPSA | Inactive precursor forms ([-2], [-4], [-7] proPSA) | Enriched in cancer tissue |
| Intact PSA | Active, uncleaved free PSA | Investigated as cancer marker |
| BPSA | Benign PSA (internally cleaved) | Associated with BPH/transition zone |
Key ratio: A lower % free PSA (fPSA/total PSA) is associated with higher risk of prostate cancer, especially in the "gray zone" PSA of 4-10 ng/mL.
PSA Density & Velocity
- PSA Density (PSAD): PSA divided by prostate volume (measured by TRUS). A PSAD >0.15 ng/mL/cc raises suspicion for cancer.
- PSA Velocity (PSAV): Rate of PSA rise over time. An increase of >0.75 ng/mL/year is a warning sign.
- PSA Doubling Time (PSADT): Rate at which PSA doubles; used to assess aggressiveness and recurrence after treatment.
Age-Specific PSA Reference Ranges
Because prostate volume (and PSA) increases with age, age-specific cutoffs were developed:
| Age Group | PSA Upper Limit |
|---|---|
| 40-49 years | 2.5 ng/mL |
| 50-59 years | 3.5 ng/mL |
| 60-69 years | 4.5 ng/mL |
| 70-79 years | 6.5 ng/mL |
PSA in Screening
- PSA was initially developed to monitor treated prostate cancer patients, but evolved into a screening tool
- It is prostate-specific, not cancer-specific - PSA can be elevated in BPH, prostatitis, and trauma
- Standard cutoff of 4.0 ng/mL is widely used, though controversial
- Conditions that raise PSA: prostate cancer, BPH, prostatitis, prostatic trauma, ejaculation, urinary retention
- Conditions/drugs that lower PSA: 5-alpha reductase inhibitors (finasteride, dutasteride) - reduce PSA by ~50% after 6-12 months
Advanced PSA Derivatives & New Biomarkers
- [-2]proPSA / Prostate Health Index (PHI): A formula combining total PSA, free PSA, and [-2]proPSA. Improves specificity for detecting clinically significant cancer.
- 4Kscore: Combines total PSA, free PSA, intact PSA, and hK2 - predicts risk of high-grade (Gleason ≥7) cancer.
- PSMA (Prostate-Specific Membrane Antigen): A glycoprotein on all prostatic epithelial cells, overexpressed in cancer. 68Ga-PSMA PET has become a major imaging tool, especially in biochemical recurrence - specificity approaches 97%, and can detect disease even at PSA levels as low as 0-0.2 ng/mL.
PSA After Treatment (Biochemical Recurrence)
- After radical prostatectomy: PSA should become undetectable. A rising PSA ≥0.2 ng/mL on two consecutive measurements = biochemical recurrence.
- After radiation therapy: PSA nadir + 2 ng/mL rise = biochemical failure (Phoenix definition).
- PSADT is the most useful tool to predict the nature (local vs. systemic) and aggressiveness of recurrence.
Source: Campbell-Walsh-Wein Urology, 3-Volume Set - Chapter 149, Block 83
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