Related Experiment Video
Updated: Mar 31, 2026
A Cognitive Fusion-guided Prostate Biopsy Using Multiparametric Magnetic Resonance Imaging and Transrectal Ultrasound
Published on: March 21, 2025
Implications for Radiation Microboosting Based on Pathology Correlations With Prostate-Specific Membrane Antigen and
Alessandra Farmer1, Leslie K Ballas1, Howard M Sandler1
1Department of Radiation Oncology, Cedars-Sinai Medical Center, Los Angeles, California.
Purpose:
Prostate-specific membrane antigen (PSMA) positron emission tomography and multiparametric magnetic resonance imaging (mpMRI) are used to contour the dominant intraprostatic lesion (DIL) when incorporating a microboost. However, it is unclear how well PSMA and mpMRI findings correlate with the true pathologic DIL. So, we performed an analysis between preoperative imaging and the final surgical specimen to identify predictors of discordance.
Methods And Materials:
This was a single-center retrospective analysis of patients with prostate cancer who underwent PSMA imaging before prostatectomy between January 2022 and December 2023. PSMA lesions were independently contoured and measured by a reviewer blinded to the final pathology. mpMRI reports were reviewed for lesion number, location, and size. Lesion size and hemigland location on imaging were compared to the final pathology. Associations between concordance or discordance and patients' demographics and clinicopathological characteristics were examined.
Results:
Of the 48 patients included, mean (SD) PSA was 13.9 (±12.9), 40% had grade group 4/5 disease, and 58% were staged as pT3 or higher. The pathologic DIL matched the hemigland of the largest PSMA/mpMRI lesion in 94/90% of cases, respectively. The median maximum lesion diameter size discrepancy between PSMA and mpMRI and final pathology was 3.4 mm (IQR, 16.3-24.8) and 4 mm (IQR, 3-9), respectively. PSMA and mpMRI underestimated lesion size in 59% and 64% of cases, respectively. On PSMA, higher prostate-specific antigen (PSA) and lower biopsy grade groups were associated with greater imaging/pathology size discrepancy on both univariate and multivariable analysis after adjusting for maximum standardized uptake volume (SUVmax); on mpMRI, higher PSA was associated with greater imaging/pathology size discrepancy on both univariate and multivariable analysis after adjusting for prostate imaging reporting and data system (PI-RADS) score (P < .05).
Conclusion:
Standard treatment margins may either overestimate or underestimate the extent of the true gross disease, depending on individual tumor characteristics. Further research is needed to develop a standardized framework for using PSMA and mpMRI to guide microboosting.
Insights
Prostate-specific membrane antigen (PSMA) positron emission tomography and multiparametric magnetic resonance imaging (mpMRI) often underestimate dominant intraprostatic lesion size compared to pathology. Higher PSA and lower biopsy grade correlate with greater discrepancies, impacting treatment margins.
Area of Science:
- Oncology
- Radiology
- Pathology
Background:
- Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) and multiparametric magnetic resonance imaging (mpMRI) are utilized for contouring the dominant intraprostatic lesion (DIL) to guide microboost radiation therapy.
- The correlation between preoperative imaging findings (PSMA PET and mpMRI) and the actual pathologic DIL is not well-established, potentially affecting treatment precision.
Purpose of the Study:
- To analyze the correlation between preoperative PSMA PET and mpMRI findings and the final surgical pathology of the dominant intraprostatic lesion (DIL).
- To identify predictors of discordance between imaging-based DIL and pathologic DIL in prostate cancer patients.
Main Methods:
- A retrospective analysis of 48 prostate cancer patients who underwent PSMA PET imaging prior to prostatectomy.
- Independent contouring and measurement of PSMA lesions by a reviewer blinded to pathology.
- Review of mpMRI reports for lesion characteristics and comparison with final pathology for size and hemigland location.
Main Results:
- The pathologic DIL matched the hemigland of the largest PSMA/mpMRI lesion in 94%/90% of cases, respectively.
- PSMA and mpMRI underestimated lesion size in 59% and 64% of cases, with median size discrepancies of 3.4 mm and 4 mm, respectively.
- Higher prostate-specific antigen (PSA) and lower biopsy grade group were associated with greater size discrepancies on PSMA PET, while higher PSA was associated with greater discrepancies on mpMRI.
Conclusions:
- Standard treatment margins may not accurately reflect the true extent of gross disease due to variations in tumor characteristics.
- Further research is necessary to develop standardized frameworks for utilizing PSMA PET and mpMRI in guiding prostate cancer treatment microboosting.
