Erectile Function After Prostate Radiation: How MRI May Help

Medscape

11 hours ago

TOPLINE:
Among patients with prostate cancer who received MRI-guided stereotactic body radiation therapy (SABR), more than 80% demonstrated 'classic' neurovascular bundle patterns and over 96% showed more than 1-cm separation of internal pudendal arteries from the prostate. These findings indicated that most patients have favorable anatomic patterns that would allow radiation oncologists to minimize radiation to structures involved in erectile function and help reduce patients' risk for posttreatment erectile dysfunction.
METHODOLOGY:
Erectile dysfunction is a common side effect for men with prostate cancer who undergo SABR. Radiation-related damage to critical nearby structures, such as the neurovascular bundles and internal pudendal arteries, likely contributes to this issue. Identifying these structures on MRI during radiation planning can minimize exposure during SABR and reduce the risk for erectile dysfunction.
Researchers analyzed 160 consecutive patients with prostate cancer (median age, 70 years) who underwent MRI-linear accelerator-based SABR between January and December 2024.
Based on the MRI scans, researchers classified neurovascular bundle patterns into classic (discrete), adherent (dispersed and adherent to the prostatic capsule), or absent.
Researchers also measured the shortest distance between internal pudendal arteries to the prostate capsule and the membranous urethral length and compared imaging features by prostate volumes, Prostate Imaging Reporting and Data System (PI-RADS) scores, lesion locations, and Gleason grade group.
TAKEAWAY:
The classic neurovascular bundle pattern was the most common, present in 80% of right-sided and 85% of left-sided evaluations, while adherent neurovascular bundles were less common, observed in 18.1% of right-sided and 13.8% of left-sided scans.
The median shortest distance between internal pudendal arteries and the prostate capsule was 2.3 cm on both sides, with only 3.1% (left side) to 3.8% (right side) of patients having a distance less than 1.0 cm.
The median membranous urethral length was 1.5 cm, with only 2.5% of men having one shorter than 1.0 cm.
Researchers found no significant association between these MRI features and prostate volumes of greater or less than 40 mL, PI-RADS scores, zonal location of the dominant intraprostatic lesion, and Gleason grade on pathology.
IN PRACTICE:
'Most patients with prostate cancer undergoing SABR demonstrated favorable anatomy of the critical structures, potentially important for potency preservation,' the authors wrote, reflecting on the fact that real-time adaptive planning, especially with MRI-guided radiotherapy, has potential for helping 'identify, define, and effectively dose-constrain these critical structures.'
SOURCE:
The study, led by Sungmin Woo, MD, PhD, NYU Grossman School of Medicine in New York City, was published online in Practical Radiation Oncology.
LIMITATIONS:
The study was conducted at a single institution, which may limit the generalizability of the findings. Additionally, the analysis excluded patients with prior prostate-directed treatments, artifacts on MRI scans, and extraprostatic extension or those without diagnostic multiparametric MRI scans, restricting applicability to patients with more advanced disease or suboptimal imaging.
DISCLOSURES:
This study did not receive any specific funding. One author disclosed serving as a consultant for Boston Scientific. The other authors declared having no conflicts of interest.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.