In this retrospective study, we compared prostate volume measured pre-procedurally by CT, TRUS, or MRI to the enucleated weight of the prostate removed during Holmium Laser Enucleation of the Prostate at a high-volume centre. We compared total prostate volume using all three modalities, as well as transitional zone only volume on MRI which can differentiate accurately between prostate zones.
For 95 patients with 114 imaging studies, baseline demographics were similar, with highest age in the CT group and highest PSA in the MRI group. Prostate volumes preoperatively were a median of 113 cc in the TRUS group, 99 cc in the CT group, and 123 cc in the MRI group. The median transitional zone volume on MRI was 67 cc preoperatively. Median enucleated weights were between 50 – 71 g. When comparing the pathology weight to the preoperative prostate volume, the pathology weight was 46g less than the TRUS volume, 51g less than the CT volume, 53g less than the MRI total volume, and 14g less than the MRI-transitional zone volume. This finding is expected, since only the transitional zone is expected to be treated during HoLEP. The total prostate volume across modalities was not statistically different in predicting enucleated volume. However, the MRI-transitional zone volume was statistically significantly more concordant with enucleated volume (p<0.001).
This indicates that all three modalities of TRUS, MRI, and CT are equally able to predict expected enucleated volume when compared to total prostate volume. However, transitional zone volume on MRI is the best predictor of enucleated volume. This is expected, since in HoLEP, the targeted area of tissue removed is the transitional zone.
Surgeons who use any of the above three modalities preoperatively for estimating total prostate volume for treatment of BPH with enucleation can be reassured that they perform comparably. However, surgeons who wish to have the most accurate preoperative prediction of enucleated volume should consider using MRI-transitional zone volume. This study may also be useful for surgeons who are early in their learning curve to assess expected enucleated volumes.
Written by: Connor M. Forbes, MD, FRCSC,1,2 Nicole L. Miller, MD, FACS3
- University of British Columbia, Vancouver, Canada
- Vancouver Prostate Centre, Vancouver, Canada
- Vanderbilt University Medical Center, Nashville, USA