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Absolute Percentage of Pattern 4 Disease as a Prognostic Measure for Intermediate-risk Prostate Cancer Treated with
R M Glicksman1, A U Kishan2, H Quon3
1Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada.
Clinical Oncology (Royal College of Radiologists (Great Britain))
|June 1, 2022
Summary
The absolute percentage of biopsied tissue positive for Gleason pattern 4 disease (APP4) is a prognostic measure for intermediate-risk prostate cancer treated with SBRT. Higher APP4 levels correlate with increased risk of biochemical failure and distant metastasis.
Area of Science:
- Oncology
- Radiation Oncology
- Prostate Cancer Research
Background:
- Intermediate-risk prostate cancer is a heterogeneous disease with variable clinical outcomes.
- Identifying reliable prognostic markers is crucial for tailoring treatment strategies.
- The absolute percentage of biopsied tissue positive for Gleason pattern 4 disease (APP4) is a potential prognostic indicator.
Purpose of the Study:
- To evaluate the prognostic impact of APP4 in men with intermediate-risk prostate cancer treated with stereotactic body radiotherapy (SBRT).
- To determine optimal APP4 cut-off points for predicting biochemical failure and distant metastasis.
- To assess the association of APP4 with oncologic outcomes in a multi-institutional pooled analysis.
Main Methods:
- A prospective, multi-institutional pooled analysis of 227 patients with intermediate-risk prostate cancer treated with SBRT.
- APP4 was calculated from pathology reports.
- Optimal cut-off points for APP4 were determined, and multivariable competing risk models were used to analyze outcomes.
Main Results:
- At 4 years, the cumulative incidence of biochemical failure was significantly higher for APP4 >5% (23.6%) compared to APP4 ≤ 5% (2.3%).
- The cumulative incidence of distant metastasis was significantly higher for APP4 >20% (12.5%) compared to APP4 ≤ 20% (1%).
- APP4 >5% was significantly associated with biochemical failure on multivariable analysis (P = 0.0004).
Conclusions:
- APP4 is a readily accessible and promising prognostic measure for intermediate-risk prostate cancer patients undergoing SBRT.
- APP4 can help stratify patients into low and high risk groups for adverse outcomes.
- Further validation in prospective trials is recommended to confirm the clinical utility of APP4.
