Top Line: While nerve injury is often responsible for iatrogenic erectile dysfunction following prostatectomy, the increased relative risk of ED over years following prostate radiation suggests vascular injury is to blame.
The Study: With everything else we’re doing with highly-conformal prostate radiation these days, why not do what we can to spare the adjacent neurovascular bundle and internal pudendal artery (IPA)? Here is an informative retroseptive imaging review of 160 men receiving prostate radiation throughout 2024 at NYU with pretreatment multiparametric prostate MRIs. On each scan, they determined (1) presence of discrete versus prostate-adherent neurovascular bundles, (2) distance between IPA and prostate, and (3) length of membranous urethra as a surrogate for distance between corporal tissue (i.e., penile bulb) and prostate. Roughly 15% had adherent neurovascular bundles, the median distance to the IPA was 2.3 cm, and the median distance to the penile bulb was 1.5 cm. In only 2-4% of cases did the IPA or corporal tissue come within 1 cm of the prostate, which is a mile in SBRT terms. The randomized phase 2 POTEN-C trial is formally evaluating neurovascular-sparing prostate SBRT with the following constraints: neurovascular bundle Dmax 30 Gy (V25Gy < 3 cc), IPA Dmax 20 Gy (V15Gy < 3 cc), and penile bulb Dmax 100% Rx (V30Gy < 3 cc).
TBL: “In conclusion, most patients with PCa demonstrated favorable anatomy for potential dose sparing of critical [erectile] structures.” | Woo, Pract Radiat Oncol 2025
The Study: With everything else we’re doing with highly-conformal prostate radiation these days, why not do what we can to spare the adjacent neurovascular bundle and internal pudendal artery (IPA)? Here is an informative retroseptive imaging review of 160 men receiving prostate radiation throughout 2024 at NYU with pretreatment multiparametric prostate MRIs. On each scan, they determined (1) presence of discrete versus prostate-adherent neurovascular bundles, (2) distance between IPA and prostate, and (3) length of membranous urethra as a surrogate for distance between corporal tissue (i.e., penile bulb) and prostate. Roughly 15% had adherent neurovascular bundles, the median distance to the IPA was 2.3 cm, and the median distance to the penile bulb was 1.5 cm. In only 2-4% of cases did the IPA or corporal tissue come within 1 cm of the prostate, which is a mile in SBRT terms. The randomized phase 2 POTEN-C trial is formally evaluating neurovascular-sparing prostate SBRT with the following constraints: neurovascular bundle Dmax 30 Gy (V25Gy < 3 cc), IPA Dmax 20 Gy (V15Gy < 3 cc), and penile bulb Dmax 100% Rx (V30Gy < 3 cc).
TBL: “In conclusion, most patients with PCa demonstrated favorable anatomy for potential dose sparing of critical [erectile] structures.” | Woo, Pract Radiat Oncol 2025