Neurovascular Sparing during Radiation Reduces Incidence of ED in Prostate Cancer

The phase 2 ERECT trial investigated the preservation of erectile function after radiotherapy that was magnetic resonance-guided with neurovascular sparing.

The 1.5T Elekta Unity MR-linear accelerator (Linac) was able to reduce the amount of radiation exposed to key structures responsible for erection in patients with prostate cancer, according to a press release from the developer, Elekta.1

The incidence of erectile dysfunction (ED) at 6 months was 6% with the Elekta Unity MR-Linac and neurovascular sparing and 21% with the same dosage without neurovascular sparing (P = .015); at 12 months, it was 8.5% vs 38%, respectively (P <.001); and at 18 months, it was 16% vs 36% (P = .019).2

The data came from the single-center, phase 2 ERECT trial (NCT04861194), which evaluated the preservation of erectile function after magnetic resonance (MR)-guided radiotherapy, which was neurovascular spared. The trial is also a sub-study of the MOMENTUM study, the MR-Linac Consortium’s platform registry.

Preliminary results from the trial were presented by clinicians at the 2025 European Society for Radiotherapy and Oncology (ESTRO) Annual Congress.

“While radiation therapy for prostate cancer has been shown to confer very high cure rates, the close proximity of nerves and blood vessels that support sexual function can mean they receive a radiation dose sufficient to interfere with their function,” stated Jochem van der Voort van Zyp, MD, PhD, a radiation oncologist at University Medical Center Utrecht and principal trial investigator, in the press release.1 “However, with the enhanced precision of MR-guidance, we gain the confidence to limit – or deescalate – the dose they receive. In short, the prostate gets the therapeutic dose while the erectile tissues receive a much lower dose, thus preserving their function.”

A total of 70 patients with intermediate-risk prostate cancer were treated with 1.5T Elekta Unity MR-Linac in the trial, all of whom received a radiation dose of 36.25 Gy over 5 fractions.

Eligible patients were 18 years or older with histologically proven adenocarcinoma of the prostate that is low-risk or intermediate risk according to NCCN risk categories.3 Additionally, patients had a pT1a/b tumor diagnosis after transurethral resection of the prostate, a domain score of 17 to 25 on the International Index of Erectile Function-5 (IIEF-5) questionnaire, and a Karnofsky performance status of 70 to 100.

Those with adjuvant/neoadjuvant use of androgen deprivation therapy, high-risk prostate cancer, prior pelvic irradiation or radical prostatectomy, and clinical evidence of metastatic disease were ineligible for trial enrollment.

The Elekta Unity MR-Linac allowed for detailed visualization of the prostate and other critical structures that are used to achieve and maintain an erection, including the neurovascular bundle, internal pudendal arteries, corpora cavernosa, and penile bulb.

The median age of patients in the experimental group was 63 years vs 68 years in the control group (P <.001); 26% vs 12%, respectively, had International Society of Urological Pathology (ISUP) grade 1 disease and 8.8% and 25%, respectively, had ISUP grade 3 disease.2

The trial’s primary end point was erectile dysfunction, defined as an erectile function score of 11 or less on the IIEF-5 questionnaire. Secondary end points include relapse-free survival, patient-reported quality of life, and acute and late gastrointestinal and genitourinary toxicity.

In the trial, patients with neurovascular sparing had higher mean IIEF-5 scores than those who did not at 6 months (21 vs 18, respectively; P = .007), 12 months (20 vs 15; P <.001), and 18 months (20 vs 14; P <.001).

In conclusion, John Christodouleas, MD, MPH, senior vice president of Medical Affairs at Elekta also added in the press release, “These results from the ERECT Trial add to a growing evidence base showing that minimizing the radiation dose to the normal tissues surrounding the prostate can improve the quality of life of men with prostate cancer. An obvious way to reduce dose to normal tissues is to ‘see what you treat’ and the best way to see the prostate and surrounding tissues is using MR-guidance.”1

References

1. Clinical trial shows more precise radiotherapy using Elekta Unity MR-Linac preserves sexual function in men with prostate cancer. News release. Elekta. May 3, 2025. Accessed May 5, 2025. https://tinyurl.com/3vnntxzd
2. Lalmahomed TA, Teunissen FR, de Boer JC, et al. The EREctile function preservation for prostate Cancer radiation Therapy (ERECT) trial (NCT04861194): preliminary results up to 18 months. Radiotherapy and Oncology. 2025; 206(1):1924-1925.
3. EREctile function preservation for prostate cancer radiation therapy (ERECT) (ERECT). ClinicalTrials.gov. Updated August 25, 2025. Accessed May 5, 2025. https://tinyurl.com/e2vchjt8