Five-Day Targeted Radiotherapy Matches Surgery for Localized Prostate Cancer With Far Lower Incontinence

On September 28, 2026, researchers at the American Society for Radiation Oncology (ASTRO) Annual Meeting presented long-term data fundamentally shifting how localized prostate cancer is treated. The phase 3 PACE-A trial demonstrated that a five-day targeted radiation regimen controls the disease just as effectively as surgical removal, while sparing patients from severe side effects.[1][4]

Men diagnosed with early-stage prostate tumors have long faced a difficult choice between radical prostatectomy and conventional radiation therapy that stretched over several weeks. The PACE-A trial sought to determine if stereotactic body radiotherapy (SBRT)—which delivers highly concentrated doses in just five outpatient sessions—could match surgical outcomes. The results provide the first randomized evidence directly comparing these two modern approaches.[1][2]

The trial enrolled 123 men across eight centers in the United Kingdom between August 2012 and February 2022. Participants, who predominantly had low- or intermediate-risk localized disease, were randomly assigned to either surgical removal of the prostate or the five-treatment SBRT protocol.[1][4]

Crucially, the trial's design intentionally excluded androgen deprivation therapy, a hormone-blocking treatment often paired with radiation to shrink tumors. Because hormone therapy carries its own suite of side effects, omitting it allowed researchers to isolate the direct functional impact of the radiation versus the scalpel.[4]

Long-Term Cancer Control

After a median follow-up of eight years, the oncological outcomes proved remarkably similar between the two cohorts. The data revealed that 91 percent of patients treated with SBRT remained free from biochemical or clinical failure. In the surgical group, 84 percent of men achieved the same failure-free status over the identical period.[1][3]

While the numerical difference slightly favored the radiation arm, researchers emphasized that the gap was not statistically significant due to the trial's size and the low overall number of cancer recurrences. Only 13 patients across the entire study experienced a clinical failure—five in the SBRT group and eight in the surgical cohort.[4]

Nicholas van As, principal investigator of the trial and a consultant clinical oncologist at The Royal Marsden NHS Foundation Trust, presented the findings to the ASTRO plenary session. He noted that the primary takeaway is the durability of both options. "Both treatments controlled the cancer extremely well, but SBRT offered clear advantages for urinary continence and sexual function," van As stated.[1][2]

The high rates of cancer control align closely with the broader PACE-B trial, which previously established that SBRT is noninferior to conventional, longer-course radiation therapy. That larger study found that 96 percent of patients with similar risk profiles remained failure-free at five years, reinforcing the efficacy of the accelerated schedule.[1][3]

Preserving Quality of Life

The most striking divergence between the two treatments emerged in the quality-of-life metrics, particularly regarding urinary function. At the five-year mark, only 8 percent of the men who received the five-day radiation therapy reported needing at least one urinary pad per day. In stark contrast, 48 percent of the surgical patients required daily pad use.[1][4]

This 40-percentage-point absolute difference in urinary incontinence represents a major consideration for patients weighing their options. Radical prostatectomy inherently risks damage to the urinary sphincter and surrounding nerves, whereas SBRT utilizes advanced imaging to map the prostate precisely. This targeted approach minimizes the radiation dose that reaches adjacent healthy tissues.[1][3]

Sexual function outcomes also heavily favored the non-surgical approach over the long term. Patient-reported erectile function scores, measured on a 25-point scale where higher numbers indicate better performance, declined in both groups over the five years. However, the median score remained at 19 for the SBRT patients, compared to just 5 for those who underwent surgery.[1]

Historically, a primary concern with prostate radiation has been the potential for gastrointestinal toxicity, as the rectum sits immediately adjacent to the prostate gland. The PACE-A data showed that moderate or substantial bowel problems were uncommon in both treatment arms, largely dispelling fears of severe late-onset bowel complications from the concentrated SBRT doses.[1][4]

At the five-year evaluation, researchers recorded only a single case of grade 2 or higher gastrointestinal toxicity in the radiation group, and none in the surgical group. Genitourinary toxicity was similarly rare, with two grade 2 or higher events following SBRT and one following prostatectomy. These figures confirm the safety profile of the five-fraction regimen.[4]

Shifting the Treatment Paradigm

These findings are expected to alter the initial conversations between urologists, radiation oncologists, and newly diagnosed patients. Because the first specialist a patient typically sees is a urologic surgeon, radiation options have sometimes been underrepresented in early consultations. The PACE-A results provide concrete, randomized data to support SBRT as a co-equal primary option.[2][4]

Amar U. Kishan, a radiation oncologist at UCLA and chair of the ASTRO Genitourinary Cancer Resource Panel, highlighted the practical impact of the data. "Together, these longer-term data give patients a more complete picture of what they can expect from each treatment," Kishan explained, noting that patients prioritize both survival and daily functioning.[1]

For health systems, the shift toward a five-day treatment model also offers logistical and financial benefits. Conventional radiation therapy requires daily hospital visits for up to eight weeks, placing a significant burden on patients and clinical resources. Condensing the curative protocol into a single week dramatically improves access and convenience.[1][2]

By removing the confounding variable of hormone suppression, the PACE-A investigators provided a pure comparison of the two local modalities. The resulting data empower patients to make decisions based strictly on the mechanical and biological differences between surgical excision and targeted radiological ablation, fundamentally clarifying the informed consent process.[3][4]

While the trial focused specifically on men with favorable intermediate-risk disease, ongoing research within the PACE program is evaluating SBRT for higher-risk prostate cancers. Until those results mature, the current data establish a clear benchmark for localized cases, proving that men no longer have to sacrifice their quality of life to achieve a cure.[1][4]