What’s New On Radiotherapy of Prostate Cancer in 2026?

How can we make prostate cancer radiotherapy more precise, reduce long-term toxicity, and improve outcomes for patients who require treatment after surgery or disease recurrence? Several important publications in 2026 address these questions, examining advances in treatment techniques, fractionation schedules, re-irradiation, and patient-reported outcomes.

New findings from the randomized HYPO-RT-PC trial provide reassuring long-term safety data for ultra-hypofractionated radiotherapy, showing no significant differences in urinary or gastrointestinal morbidity compared with conventional treatment after approximately a decade of follow-up.

Meanwhile, a study conducted within the PROstate PROTON trial investigates whether proton-based whole-pelvic radiotherapy can reduce radiation exposure to the bowel and bladder while maintaining reliable target coverage, even when accounting for anatomical variations. For patients requiring radiotherapy after radical prostatectomy, new prospective data evaluate the long-term outcomes of moderately hypofractionated treatment, identifying important predictors of late urinary toxicity and highlighting the need for continued monitoring beyond the first two years.

Salvage treatment for locally recurrent prostate cancer is another important area of investigation. A study of MRI-guided adaptive re-irradiation reports promising early local control, while a comprehensive review from the Reirradiation Collaborative Group (ReCOG) examines the available prospective evidence and identifies major differences in dose fractionation, target delineation, and organ-at-risk constraints.

Beyond treatment techniques, another HYPO-RT-PC analysis raises an important question about toxicity assessment: Are clinicians accurately recognizing the symptoms experienced by their patients? The findings reveal substantial discrepancies between physician-rated toxicity and patient-reported urinary, bowel, and sexual health outcomes.

Together, these six publications explore how prostate cancer radiotherapy is evolving, from shorter treatment schedules and improved dose distribution to more individualized salvage approaches and better recognition of long-term treatment-related symptoms. Here are six recent publications worth reading and what their findings mean for prostate cancer radiotherapy in 2026.

MRI-Guided Adaptive Re-Irradiation Shows Promising Local Control in Recurrent Prostate Cancer Salvage radiotherapy for locally recurrent prostate cancer remains challenging, particularly for patients who have already received high-dose radiation to the prostate. A study published in Clinical and Translational Radiation Oncology reports encouraging outcomes with stereotactic MR-guided adaptive radiotherapy (SMART), suggesting that daily adaptive treatment may provide an effective non-invasive salvage option for carefully selected patients.

The retrospective, single-center study evaluated 19 patients with biopsy-confirmed, non-metastatic, hormone-sensitive prostate cancer recurrence following previous radiotherapy. The median interval between the initial radiation course and salvage treatment was 87 months, and the median age at re-irradiation was 74 years.

Patients received 30–35 Gy in five fractions, delivered on alternate days. Treatment targeted the whole prostate gland in 12 patients, half of the gland in five, and the seminal vesicles in two. Androgen deprivation therapy was also prescribed to selected patients.

An important feature of the approach was the use of daily MRI-based plan adaptation, real-time tumor tracking, and automated beam gating. All 95 treatment fractions underwent online adaptation, with individualized organ-at-risk constraints calculated using equivalent dose in 2-Gy fractions (EQD2) to account for previous radiation exposure.

At a median follow-up of 21 months, biochemical relapse-free survival was 73.7%, while progression-free survival reached 94.7% at one year and 89.4% at two years. Local control was 100% at both one and two years, with an estimated three-year local control rate of 84.2%. All patients were alive at the time of analysis.

The toxicity profile was encouraging but not without clinically important complications. Acute grade 2 genitourinary toxicity occurred in 21% of patients, with no acute grade 3 or higher events. However, three patients (15.7%) developed late grade 3 genitourinary toxicity.

No grade 2 or higher gastrointestinal toxicity was observed. Two patients experienced contralateral intraprostatic recurrence following partial-gland treatment, raising concerns about the potential for untreated microscopic disease outside the targeted region. The study also found that achieving a post-treatment PSA nadir of ≤0.2 ng/mL was associated with better two-year progression-free survival (91.7% versus 42.9%; P=0.045).

Although limited by its small sample size, retrospective design, and relatively short follow-up, the findings support further investigation of SMART re-irradiation for localized prostate cancer recurrence. The individualized EQD2-based planning approach may be particularly relevant for balancing disease control against cumulative radiation exposure to the bladder, rectum, and urethra.

The results suggest that MRI-guided adaptive re-irradiation is feasible and offers promising early local control, but late urinary toxicity and the risk of recurrence outside focal treatment volumes remain important considerations. HYPO-RT-PC Confirms Similar 10-Year Toxicity With Ultra-Hypofractionated and Conventional Prostate Radiotherapy Can prostate cancer radiotherapy be delivered in just seven sessions without increasing the risk of long-term urinary and gastrointestinal complications?

A new analysis of the randomized phase III HYPO-RT-PC trial, published in Radiotherapy and Oncology, provides additional reassurance about the long-term safety of ultra-hypofractionated radiotherapy for localized prostate cancer. Using Swedish national healthcare registers, researchers examined genitourinary (GU) and gastrointestinal (GI) morbidity more than a decade after treatment, comparing men who received ultra-hypofractionated radiotherapy with those treated using conventional fractionation.

The analysis included 1,082 patients from the original randomized trial, with 541 patients in each treatment group, alongside 2,705 age- and region-matched men without prostate cancer. Patients received either 42.7 Gy in seven fractions, delivered three times weekly, or 78 Gy in 39 fractions, delivered five times weekly.

Hormonal therapy was not permitted in the original trial. Most participants had intermediate-risk prostate cancer, and the majority were treated using three-dimensional conformal radiotherapy. With approximately 11 years of median follow-up in both radiotherapy groups, investigators found no statistically significant differences in long-term GU or GI morbidity between the two fractionation schedules.

Using broad diagnostic and intervention codes, the 10-year cumulative incidence of GU events was 17% with ultra-hypofractionation versus 19% with conventional radiotherapy (adjusted HR 0.95; 95% CI, 0.71–1.25). For GI events, the corresponding rates were 17% versus 14% (adjusted HR 1.24; 95% CI, 0.91–1.69), also without a statistically significant difference.

When researchers applied narrower definitions restricted to conditions more strongly associated with radiotherapy, 10-year GU event rates were identical at 9% in both groups, while GI event rates were 6% versus 4%, respectively. The latter difference was not statistically significant.

The study also compared patients receiving radiotherapy with men from the general population. Across both radiotherapy groups, the estimated excess 10-year cumulative incidence was 5–8 percentage points for GU events and 4–5 percentage points for GI events, depending on the definitions used.

No statistically significant increase in GU- or GI-related mortality was identified. Unlike conventional physician-reported toxicity assessments, this analysis used healthcare records to identify hospitalizations, invasive procedures, and other clinically significant complications, providing an additional perspective on long-term treatment safety.

However, registry-based outcomes cannot reliably establish whether individual events were caused by radiotherapy. The analysis also primarily captured more serious complications, while most patients had received older three-dimensional conformal techniques rather than contemporary IMRT or VMAT.

The findings reinforce the long-term safety of ultra-hypofractionated prostate radiotherapy, showing that a seven-fraction regimen did not produce a statistically significant increase in serious urinary or gastrointestinal morbidity compared with conventional treatment over approximately a decade of follow-up.

The results also highlight that radiotherapy-related morbidity remains clinically relevant regardless of fractionation schedule, making long-term toxicity assessment an essential part of treatment selection and patient counseling. Proton Therapy Reduces Bowel and Bladder Radiation Exposure in High-Risk Prostate Cancer Can proton therapy reduce radiation exposure to healthy pelvic organs without compromising treatment accuracy in patients with high-risk prostate cancer?

A study published in Radiotherapy and Oncology reports that proton-based whole-pelvic radiotherapy significantly reduces bowel and bladder radiation exposure compared with photon therapy, while maintaining comparable target coverage despite anatomical changes during treatment. The analysis was conducted within the PROstate PROTON Trial 1 (NCT05350475), an ongoing multicenter randomized clinical trial comparing proton and photon radiotherapy in high-risk prostate cancer.

Researchers evaluated treatment plans from five patients receiving proton-based whole-pelvic radiotherapy at the Danish Centre for Particle Therapy. Five independent photon therapy centers developed comparative plans for the same patients, allowing a multicenter assessment of dosimetric differences.

Both treatment approaches prescribed 78 Gy to the high-dose prostate target and 56 Gy to lower-dose targets, including the elective pelvic lymph nodes, in 39 fractions, using a simultaneous integrated boost. To assess whether the dosimetric advantages of proton therapy persisted during treatment, investigators evaluated original plans, simulated setup uncertainties, and recalculated doses using repeat CT scans obtained during weeks one and three.

The findings demonstrated significant reductions in bowel radiation exposure with proton therapy. Across the evaluated plan types, proton therapy reduced bowel V35Gy, representing the percentage of bowel volume receiving at least 35 Gy, by approximately 11 percentage points compared with photon therapy (P=0.02).

The mean bowel dose was also significantly reduced by 13.8 Gy (P=0.001), reaching 12.9 Gy with proton treatment. Similarly, mean bladder dose was reduced by 18.4 Gy with proton therapy (P=0.02). Although lower anorectal radiation exposure was observed with proton treatment, differences in mean dose and V30Gy did not reach statistical significance.

No consistent advantage was demonstrated for high-dose normal tissue metrics. Importantly, target coverage remained robust with both modalities across the evaluated scenarios, including those incorporating anatomical changes and positioning uncertainties. The proton plans preserved their normal tissue-sparing advantages even after accounting for inter-fractional variations, addressing concerns that the physical characteristics of proton beams could make treatment more sensitive to daily changes in pelvic anatomy.

The findings are particularly relevant for whole-pelvic radiotherapy, where irradiation of the prostate and elective pelvic lymph nodes increases the volume of bowel and bladder exposed to radiation. However, this was a dosimetric planning study involving only five patients, rather than a randomized comparison of clinical outcomes.

Consequently, the observed reductions in radiation exposure cannot yet be interpreted as evidence of lower toxicity or improved survival. Differences in planning approaches across participating centers may also have influenced the comparisons. The study suggests that proton-based whole-pelvic radiotherapy can maintain reliable target coverage while substantially reducing low- and intermediate-dose exposure to surrounding organs.

Whether these dosimetric advantages translate into clinically meaningful reductions in treatment-related toxicity remains to be established through ongoing randomized trials. Postoperative Hypofractionated Radiotherapy Shows Promising Disease Control but Late Urinary Toxicity Remains a Concern in Prostate Cancer Moderately hypofractionated radiotherapy offers a shorter postoperative treatment schedule for prostate cancer, but concerns remain about urinary complications that may develop or worsen years after treatment.

A prospective study published in Clinical and Translational Radiation Oncology reports encouraging disease control following postoperative moderate hypofractionation while identifying important predictors of late genitourinary toxicity. Researchers at Peking University First Hospital evaluated 278 patients who received postoperative radiotherapy between 2018 and 2020, including patients treated for adverse pathological features after radical prostatectomy and those receiving early salvage or salvage radiotherapy following PSA recurrence.

All patients received 62.75 Gy in 25 fractions to the prostate bed, corresponding to 2.51 Gy per fraction. Pelvic lymph node irradiation was administered to 95% of patients, generally at 47.5 Gy in 25 fractions, while 73% received androgen deprivation therapy. Daily cone-beam CT was used for image guidance.

After a median follow-up of 50 months, the study demonstrated favorable disease control. Four-year event-free survival was 81.0%, biochemical progression-free survival was 86.9%, prostate cancer-specific survival was 99.6%, and overall survival reached 97.2%. However, late urinary toxicity continued to increase beyond the first two years following treatment.

The cumulative incidence of grade 2 or higher genitourinary toxicity increased from 19.5% at two years to 28.4% at four years. Hematuria and urinary incontinence were the most frequent complications. Four-year rates of grade ≥2 hematuria and urinary incontinence were 11.4% and 22.1%, respectively.

Grade ≥3 urinary incontinence occurred in 5.1% of patients by four years. Importantly, the investigators identified factors associated with increased urinary toxicity. Patients whose bladder V60Gy exceeded 12.35% had a significantly higher four-year incidence of grade ≥2 hematuria compared with those below this threshold (16.3% versus 6.8%; P=0.020).

Pre-existing urinary incontinence was another important predictor. Patients with grade 2–3 incontinence before radiotherapy experienced higher four-year rates of grade ≥2 incontinence than those with less severe baseline symptoms (31.2% versus 19.1%; P=0.025). The study also observed higher rates of urinary incontinence among patients who underwent cystoscopy after radiotherapy, although this association may reflect differences in underlying urinary problems rather than a direct effect of the procedure.

In contrast, late gastrointestinal toxicity was uncommon, with grade ≥2 events reported in only four patients (1.4%) and no grade 3 gastrointestinal toxicity observed. The findings highlight the importance of bladder dose constraints, assessment of baseline urinary function, and continued monitoring beyond two years after postoperative radiotherapy.

However, the single-center, nonrandomized design, heterogeneous use of androgen deprivation therapy, and absence of a conventionally fractionated comparison group limit conclusions about the relative safety of different fractionation schedules. The proposed bladder V60Gy threshold also requires external validation.

The study supports postoperative moderate hypofractionation as a feasible treatment approach with encouraging disease control, while demonstrating that late urinary toxicity remains clinically relevant and may continue to emerge several years after treatment. ReCOG Review Highlights the Need for Standardized Prostate Cancer Re-Irradiation Approaches Re-irradiation is increasingly being considered for patients with locally recurrent prostate cancer following previous radiotherapy, offering a potential alternative to salvage surgery or other local treatments.

However, uncertainty remains about optimal radiation doses, target volumes, and how to protect organs that have already received substantial radiation exposure. A new review from the Reirradiation Collaborative Group (ReCOG), published in Clinical and Translational Radiation Oncology, examines prospective evidence for salvage stereotactic body radiotherapy (SBRT) and brachytherapy, highlighting substantial variation in treatment planning and toxicity outcomes.

Researchers identified 20 published prospective studies and 11 ongoing studies evaluating prostate cancer re-irradiation. The published studies included 10 using SBRT, nine using brachytherapy, and one incorporating both approaches. No phase III trials were identified.

Treatment schedules varied considerably. Published SBRT studies used doses ranging from 25–42.5 Gy in five fractions or 36–38 Gy in six fractions, generally delivered on alternate days. Brachytherapy studies evaluated low-dose-rate (LDR), high-dose-rate (HDR), and pulsed-dose-rate approaches, with different fractionation schedules and prescription methods.

Target delineation also differed across studies. Some investigators treated only the recurrent tumor using focal radiotherapy, while others irradiated the entire prostate, sometimes incorporating a simultaneous integrated boost to visible disease. Most studies used MRI and PET/CT to identify recurrence, but requirements for biopsy confirmation, target margins, and baseline urinary function were inconsistent.

A particularly important finding was the lack of standardized organ-at-risk dose constraints. Bladder, urethral, and rectal dose limits differed substantially between studies, and none of the published prospective studies incorporated cumulative organ-at-risk constraints accounting for radiation received during the initial treatment.

Only one ongoing study included such an approach. This is a major challenge in re-irradiation, where the combined radiation exposure from multiple treatment courses may influence late complications. Most prospective studies reported acceptable genitourinary and gastrointestinal toxicity, but severe adverse events occurred in some cohorts.

For example, certain whole-gland SBRT series reported late grade 3 genitourinary toxicity rates of approximately 8–16%. Some brachytherapy studies also reported substantial urinary complications, including urethral strictures, urinary obstruction, and fistulas. In one small LDR brachytherapy study, 12% of patients developed grade 4 prostate–rectal fistulas, illustrating the potential risks of salvage treatment in previously irradiated tissues.

Although focal treatment may reduce radiation exposure to surrounding organs, the review found insufficient evidence to establish whether it provides a better balance of disease control and toxicity than whole-gland re-irradiation. The authors also emphasized that short follow-up in several published series may underestimate late complications, which can emerge years after treatment.

An important limitation is the heterogeneity of available evidence, including differences in treatment selection, dose schedules, toxicity grading, and follow-up duration. The review was also not conducted as a formal PRISMA systematic review. The ReCOG review concludes that prostate re-irradiation with SBRT or brachytherapy is a feasible salvage option for selected patients, but standardized treatment planning and stronger prospective evidence are urgently needed.

The authors recommend delivering re-irradiation within prospective studies or registries, with careful patient selection, robust target delineation, systematic reporting of cumulative radiation doses, and comprehensive long-term toxicity assessment.