Do clinically insignificant tumors of the prostate exist?

Area of Science:

• Urology
• Oncology
• Pathology

Background:

• Discrepancies between prostate biopsy and surgical specimens challenge the concept of clinically insignificant impalpable prostate tumors.
• Prostate-specific antigen (PSA) screening detects many impalpable prostate cancers (PCs) at stage T1c.
• Incidental impalpable tumors found during transurethral resection (stage T1a/b) may represent clinically insignificant disease.

Purpose of the Study:

• To characterize latent, impalpable prostate cancers.
• To determine the incidence of clinically insignificant prostate cancers among hypothetical stage T1 cancers found incidentally at autopsy.

Main Methods:

• Examined 40 cases of impalpable prostate cancers from 212 prostate autopsy specimens.
• Subjects were men aged 30-98 who died from non-prostate-related causes.

Main Results:

• The majority of stage T1 histological PCs (57.5%) had a Gleason score of 2-4; 30% had a Gleason score of 5-6.
• 67.5% of stage T1 histological cancers had a volume <1 cm³.
• Tumors <1 cm³ were predominantly well-differentiated (Gleason 2-4) and confined within the prostatic capsule (96.55%).

Conclusions:

• Impalpable prostate cancers are predominantly low-volume, well-differentiated tumors, indicating clinical insignificance.
• These characteristics likely apply to impalpable prostate cancers detected in clinical practice.