SIU 2017: Atypical Small Acinar Proliferation: Progression to Clinically Significant Prostate Cancer?

Lisbon, Portugal ( Guideline recommendation for atypical small acinar proliferation (ASAP) diagnosed on prostate biopsy recommends repeat biopsy within 3-6 months after initial diagnosis. The authors attempted to discern the rate of detecting clinically significant prostate cancer on subsequent biopsy as well as any predictors associated with progression using the 5 tier Gleason grade grouping system (GGGS).

A retrospective chart review of patients who underwent prostate biopsy at the University of Texas Medical Branch at Galveston from 2008 to 2015 was performed. GGGS and D'Amico risk stratification were used to report pathology and prostate cancer risk stratification, respectively. 

A total of 593 patients who underwent prostate needle biopsy were identified, of which 27 (4.6%) had the diagnosis of ASAP. Of these, 11 (41%) had a repeat biopsy. Median time from initial ASAP diagnosis to repeat biopsy was 147 days (IQR: 83.5-247.0). Of the 11 patients diagnosed with ASAP, distribution across the GGGS on follow-up biopsy is as follows: 7 (63.6%) benign, 3 (27.3%) GG1 prostate cancer and one (9.1%) GG2 prostate cancer. In a logistic regression analysis, ASAP was not associated with subsequent diagnosis of prostate cancer (OR=0.46, 95% CI: 0.064 to 3.247, p=0.432). In a linear regression analysis, there was no association between ASAP and classification of cancer risk.

The authors concluded that patients diagnosed with ASAP on index biopsy managed according to NCCN recommendations, are more likely to be diagnosed with benign pathology and clinically insignificant prostate cancer upon repeat biopsy. These findings require further external validation of the results in a large cohort of patients in order to discern the appropriateness and timeliness of repeat biopsy among patients diagnosed with ASAP.

Presented by: Kosarek C
Affiliation: The University of Texas Medical Branch, Galveston, United States

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre.Twitter: @GoldbergHanan at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal