MP58-10: Modeling the Oncological Outcomes of Partial Prostatectomy in a Cohort of Patients Who Underwent Radical Prostatectomy for Localized Prostate Cancer
Sunday, May 5, 2024 1:00 PM to 3:00 PM · 2 hr. (US/Central)
221C
Abstract
Information
Full Abstract and Figures
Author Block
Adriana M Pedraza Bermeo*, Jaya S Chavali, Carter Mikesell, Roxana Ramos-Carpinteyro, Nicolas Soputro, Jihad Kaouk, CLEVELAND, OH
Introduction
Long-term follow-up studies consistently show that localized prostate cancer patients on active surveillance have survival rates similar to those receiving radical treatments. However, this comes with a higher risk of metastatic disease and increased need for hormonal therapy. Given the dominant lesion's role in metastatic progression and the importance of preserving post-treatment function, interest in focal therapies and organ-sparing surgery is growing. Yet, due to prostate cancer's multifocal nature, questions persist about the oncologic safety of these methods. Our objective is to identify predictive factors for overlooking cancer foci during Partial Prostatectomy (PP).
Methods
We simulated PP using quarter-mount prostate samples from 64 men who underwent radical prostatectomy from August 2014 to August 2023 and met the PP criteria: PSA =10 ng/ml, clinical stage = T2b, ISUP Grade Group = 2, and a unilateral dominant lesion on mpMRI with matching positive biopsies. Data were prospectively collected in an IRB-approved database, followed by a retrospective analysis.
Results
At diagnosis, median age was 64 (IQR 53-78) and PSA was 5.5 ng/mL (IQR 1-10). The upgrading and upstaging rates were 40% (26/64) and 46% (30/64), respectively. PP would have left residual cancer in 25% (16/64) of cases. Factors predicting missed cancer included cribriform architecture, >45% positive cores, mpMRI lesion length =14 mm, and prostate volume =36 cc (AUC = 0.86). While mpMRI found the dominant lesion in 89% (57/64) of patients, it underestimated size in 70%, with a 4.5 mm mean discrepancy between radiological (13.2 mm) and pathological (17.7 mm) measurements. Most of the missed cancers would have been located in the contralateral peripheral zone and at the prostate apex.
Conclusions
PP offers an appealing option for managing localized prostate cancer in selected patients. The risk of overlooking cancerous foci—particularly in those with cribriform architecture and a significant proportion of positive biopsy cores—should not be underestimated. Given the inherent limitations of mpMRI in sizing the tumor, rigorous assessment of safety margins becomes imperative. Our study underscores variables warranting attention in the execution of these tailored interventions.
Source Of Funding
None
Author Block
Adriana M Pedraza Bermeo*, Jaya S Chavali, Carter Mikesell, Roxana Ramos-Carpinteyro, Nicolas Soputro, Jihad Kaouk, CLEVELAND, OH
Introduction
Long-term follow-up studies consistently show that localized prostate cancer patients on active surveillance have survival rates similar to those receiving radical treatments. However, this comes with a higher risk of metastatic disease and increased need for hormonal therapy. Given the dominant lesion's role in metastatic progression and the importance of preserving post-treatment function, interest in focal therapies and organ-sparing surgery is growing. Yet, due to prostate cancer's multifocal nature, questions persist about the oncologic safety of these methods. Our objective is to identify predictive factors for overlooking cancer foci during Partial Prostatectomy (PP).
Methods
We simulated PP using quarter-mount prostate samples from 64 men who underwent radical prostatectomy from August 2014 to August 2023 and met the PP criteria: PSA =10 ng/ml, clinical stage = T2b, ISUP Grade Group = 2, and a unilateral dominant lesion on mpMRI with matching positive biopsies. Data were prospectively collected in an IRB-approved database, followed by a retrospective analysis.
Results
At diagnosis, median age was 64 (IQR 53-78) and PSA was 5.5 ng/mL (IQR 1-10). The upgrading and upstaging rates were 40% (26/64) and 46% (30/64), respectively. PP would have left residual cancer in 25% (16/64) of cases. Factors predicting missed cancer included cribriform architecture, >45% positive cores, mpMRI lesion length =14 mm, and prostate volume =36 cc (AUC = 0.86). While mpMRI found the dominant lesion in 89% (57/64) of patients, it underestimated size in 70%, with a 4.5 mm mean discrepancy between radiological (13.2 mm) and pathological (17.7 mm) measurements. Most of the missed cancers would have been located in the contralateral peripheral zone and at the prostate apex.
Conclusions
PP offers an appealing option for managing localized prostate cancer in selected patients. The risk of overlooking cancerous foci—particularly in those with cribriform architecture and a significant proportion of positive biopsy cores—should not be underestimated. Given the inherent limitations of mpMRI in sizing the tumor, rigorous assessment of safety margins becomes imperative. Our study underscores variables warranting attention in the execution of these tailored interventions.
Source Of Funding
None