This study aimed to evaluate the clinical acceptability of artificial intelligence (AI)-based organ segmentations on pretreatment CT images of prostate cancer patients using manual organ delineations as a reference. Paired AI-based segmentations and manual delineations of the prostate, urinary bladder, and rectum were evaluated by three observers, according to a 4-grade Likert-scale, based on quality criteria, developed through a Delphi process. Visual grading characteristics (VGC) analysis was performed. When comparing the ratings of AI-based (n = 360) and manual delineations (n = 360), the area under the VGC-curve (AUCVGC) was 0.36 (95% CI 0.27-0.44), 0.35 (95% CI 0.28-0.41), and 0.3 (95% CI 0.22-0.40) for the prostate, urinary bladder, and rectum, respectively, indicating inferior ratings for the algorithm. Few AI segmentations (8%) were considered clinically unacceptable, while in 67% no or minor changes were needed. Despite superior ratings for manual delineations, most AI-segmentations needed no or minor changes, indicating clinical acceptability.

Abstract Background Metastasis-directed stereotactic body radiotherapy (MD-SBRT) has shown promise in retrospective and phase II studies for oligometastatic hormone-sensitive prostate cancer. However, prospective randomized phase III data—particularly in newly diagnosed cases and in combination with androgen deprivation therapy and next-generation androgen receptor pathway inhibitors—are limited. The METRO trial investigates the addition of MD-SBRT to standard of care in patients with prostate-specific membrane antigen (PSMA) PET/CT-detected oligometastatic disease. Methods METRO is a multicentre, double arm, open-label, phase III randomized trial comparing MD-SBRT plus standard of care versus standard of care alone in patients with one to three PSMA PET/CT-detected distant metastases. The PSMA-RADS scale is used to support inclusion, and only patients with PSMA-RADS 4 or 5 lesions in bone or non-regional lymph nodes are eligible. Standard of care includes time-limited androgen deprivation therapy and/or androgen receptor pathway inhibitor, as well as local radiotherapy to the prostate or prostate bed. Patients are stratified by disease type (synchronous or metachronous) and metastasis location (lymph node/bone). The primary endpoint is biochemical progression-free survival; secondary endpoints include time to castration-resistant prostate cancer, adverse events, and health-related quality of life. The intervention is prescribed either 30 Gy in 3 fractions or 40 Gy in 5 fractions and delivered by stereotactic treatment principles. Discussion The METRO trial investigates the added value of combining MD-SBRT with time-limited intensified hormonal therapy in both synchronous and metachronous oligometastatic hormone-sensitive prostate cancer staged by PSMA‑PET/CT. The use of the PSMA-RADS scale for inclusion ensures a standardized and reproducible approach for patient selection. Trial registration ClinicalTrials.gov Identifier: NCT04983095.

BACKGROUND:HYPO-RT-PC is a phase 3 trial comparing ultra-hypofractionated and conventionally fractionated radiotherapy in intermediate-to-high-risk localised prostate cancer. This 10-year update reports long-term efficacy and toxicity outcomes. METHODS:In this open-label, randomised, phase 3, non-inferiority trial done in ten centres in Sweden and two in Denmark, we recruited men aged 75 years or younger with intermediate-risk or high-risk prostate cancer and a WHO performance status between 0 and 2. Previous or current androgen deprivation therapy was not permitted. Patients were randomly assigned (1:1) to ultra-hypofractionated radiotherapy (42·7 Gy in seven fractions, 3 days per week for 2·5 weeks) or conventionally fractionated radiotherapy (78·0 Gy in 39 fractions, 5 days per week for 8 weeks). Randomisation was performed with a minimisation algorithm balancing T stage, Gleason score, prostate-specific antigen, and trial centre. The primary endpoint was failure-free survival, defined as time from randomisation to the first occurrence of biochemical failure, evidence of clinical progression, initiation of androgen deprivation therapy, or death from prostate cancer, analysed in the per-protocol population. The non-inferiority margin was 4% at 5 years and had previously been met, corresponding to a critical hazard ratio (HR) limit of 1·338. Toxicity was assessed using the Radiation Therapy Oncology Group morbidity scale. Here, we report long-term efficacy and safety results at 10 years. The trial is registered with the ISRCTN registry, ISRCTN45905321, and is closed. FINDINGS:Between July 1, 2005, and Nov 4, 2015, 1200 patients were randomly assigned to conventional fractionated radiotherapy (n=602) or ultra-hypofractionated radiotherapy (n=598). Ten patients withdrew consent, eight were found to be ineligible, and two died of reasons unrelated to prostate cancer. 1180 patients constituted the per-protocol population (591 in the conventional fractionation group and 589 in the ultra-hypofractionation group). After a median follow-up of 10·6 years (IQR 9·0-13·0) in the conventional fractionation group and 10·7 years (9·1-12·7) in the ultra-hypofractionation group, 205 and 178 primary events were observed, respectively. 10-year failure-free survival was 65% (95% CI 61-69) in the conventionally fractionated group and 72% (68-76) in the ultra-hypofractionated group. The adjusted HR for the primary endpoint was 0·84 (95% CI 0·69-1·03; Cox regression analysis), confirming non-inferiority. The 10-year cumulative incidence of late grade 2 or worse genitourinary toxic effects was 30% (95% CI 26-34) in the conventional fractionation group and 28% (24-32) in the ultra-hypofractionated group (HR 1·01, 95% CI 0·81-1·25; p=0·95). For late grade 2 or worse gastrointestinal toxic effects, the corresponding figures were 14% (95% CI 11-18) and 14% (11-17; HR 0·94, 95% CI 0·70-1·28; p=0·72). INTERPRETATION:This 10-year follow-up confirms the non-inferiority of the ultra-hypofractionated radiotherapy regimen compared with the conventionally fractionated, with similar toxicity profiles. The findings support the seven-fraction schedule as a safe, effective, and practical standard-of-care option for patients with intermediate-risk prostate cancer. FUNDING:The Nordic Cancer Union, the Swedish Cancer Society, the Swedish Research Council, the Swedish Prostate Cancer Association, and Cancerforskningsfonden i Norrland.

Objective: This article presents a summary of the 2025 Swedish prostate cancer guidelines, focusing on recurrence after local treatment, metastatic disease, and castration-resistant prostate cancer. Results: The 2025 Swedish guidelines introduce several important updates. Prostate specific membrane antigen (PSMA)-PET/CT is recommended only when PSA exceeds 0.2 µg/L, and reporting should follow the defined PSMA-RADS-scale. PSMA-PET/CT is preferred over lymph-node dissection for staging. A strong recommendation is issued for radiotherapy to the primary tumour in all oligometastatic men with a life expectancy > 5 years, whereas metastasis-directed therapy is restricted to clinical trials. Systemic treatment pathways now prioritise androgen receptor pathway inhibitors (ARPI) plus androgen deprivation therapy (ADT), with triple therapy (including docetaxel) used more selectively. Pathway-specific staging algorithms have been revised. The oly (ADP-ribose) polymerase inhibitor (PARPi) section has expanded, with broader genomic-based selection and integration into treatment sequencing. Two new chapters and an appendix address cardiovascular risk assessment before ARPI or chemotherapy. Supportive care is substantially strengthened. Compared with the EAU-EANM-ESTRO-ESUR-ISUP-SIOG Guidelines on Prostate Cancer 2025, the Swedish guidelines 2025 applies PSMA-PET/CT more conservatively, restricts PSMA-guided nodal salvage therapy, and issues a more universal recommendation for local radiotherapy in oligometastatic disease. The Swedish guidelines 2025 prioritise ARPI + ADT and limit triple therapy and PARPi combinations due to regulatory and reimbursement constraints. PARPi are largely reserved for BRCA1/2-mutated disease. The Swedish guidelines 2025 provide a more comprehensive framework for rehabilitation and survivorship. Conclusions: The 2025 Swedish prostate cancer guidelines introduce multiple new recommendations and differ in several aspects from the European guidelines.

There is a long history of curative treatment of prostate cancer. However, as prostate cancer often grows very slowly, and symptoms do not have time to develop during a person's lifetime, a more tentative approach has become more and more common in many cases. This may be through either watchful waiting or active surveillance. In the first case palliative hormonal treatment is given in the case of progression, in the latter curative treatment would be the choice. When treatment is deemed necessary for localized disease, surgery and radiotherapy are considered equivalent in terms of efficacy and overall risk of side effects. For locally advanced disease, radiotherapy is the recommended first-hand choice outside the SPCG 15 study. Focal treatment, which may lead to less side effects than surgery or radiotherapy, is not recommended outside trial settings due to lack of long-term follow-up data.

BACKGROUND:Data on functional and psychological side effects following curative treatment for prostate cancer are lacking from large, contemporary, unselected, population-based cohorts. OBJECTIVE:To assess urinary symptoms, bowel disturbances, erectile dysfunction (ED), and quality of life (QoL) 12 mo after robot-assisted radical prostatectomy (RARP) and radiotherapy (RT) using patient-reported outcome measures in the Swedish prostate cancer database. DESIGN, SETTING, AND PARTICIPANTS:This was a nationwide, population-based, cohort study in Sweden of men who underwent primary RARP or RT between January 1, 2018 and December 31, 2020. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS:Absolute proportions and odds ratios (ORs) were calculated using multivariable logistic regression, with adjustment for clinical characteristics. RESULTS AND LIMITATIONS:A total of 2557 men underwent RARP and 1741 received RT. Men who underwent RT were older (69 vs 65 yr) and had more comorbidities at baseline. After RARP, 13% of men experienced incontinence, compared to 6% after RT. The frequency of urinary bother was similar, at 18% after RARP and 18% after RT. Urgency to defecate was reported by 14% of men after RARP and 34% after RT. At 1 yr, 73% of men had ED after RARP, and 77% after RT. High QoL was reported by 85% of men after RARP and 78% of men after RT. On multivariable regression analysis, RT was associated with lower risks of urinary incontinence (OR 0.25, 95% confidence interval [CI] 0.19-0.33), urinary bother (OR 0.79, 95% CI 0.66-0.95), and ED (OR 0.54, 95% CI 0.46-0.65), but higher risk of bowel symptoms (OR 2.86, 95% CI 2.42-3.39). QoL was higher after RARP than after RT (OR 1.34, 95% CI 1.12-1.61). CONCLUSIONS:Short-term specific side effects after curative treatment for prostate cancer significantly differed between RARP and RT in this large and unselected cohort. Nevertheless, the risk of urinary bother was lower after RT, while higher QoL was common after RARP. PATIENT SUMMARY:In our study of patients treated for prostate cancer, urinary bother and overall quality of life are comparable at 1 year after surgical removal of the prostate in comparison to radiotherapy, despite substantial differences in other side effects.

Benign prostatic hyperplasia (BPH) is a non-neoplastic proliferative disease producing lower urinary tract symptoms related to the resulting enlarged prostate. BPH is pathologically characterized by hyperplastic growth in both epithelial and stromal compartments. Androgen signaling is essential for prostate function and androgen blockade is the second-line medical therapy to relieve symptoms of BPH. Here we examined the prostates of probasin promoter-driven prolactin (Pb-PRL) transgenic mice, a robust model of BPH that spontaneously develops prostate enlargement, to investigate prostate regression in response to surgical castration. Serial ultrasound imaging demonstrated very uniform self-limited growth of Pb-PRL prostate volume that is consistent with the benign, limited cellular proliferation characteristic of BPH and that contrasts with the highly variable, exponential growth of murine prostate cancer models. Castration elicited only a partial reduction in prostate volume, relative to castration-induced regression of the normal prostate gland. The anti-androgen finasteride induced a diminished reduction of Pb-PRL prostate volume versus castration. The limited extent of Pb-PRL mouse prostate volume regression correlated with the initial volume of the stromal compartment, suggesting a differential sensitivity of the epithelial and stromal compartments to androgen withdrawal. Indeed, two-dimensional morphometric analyses revealed a distinctly reduced rate of regression for the stromal compartment in Pb-PRL mice. The myofibroblast component of the Pb-PRL prostate stroma appeared normal, but the stromal compartment contained more fibroblasts and extracellular collagen deposition. Like normal prostate, the rate of regression of the Pb-PRL prostate was partially dependent on TGFß and TNF signaling, but unlike the normal prostate, the extent of castration-induced regression was not affected by TGFß or TNF blockade. Our studies show that androgen deprivation can effectively reduce the overall volume of hyperplastic prostate, but the stromal compartment is relatively resistant, suggesting additional therapies might be required to offer an effective treatment for the clinical manifestations of BPH.

Purpose: Meticulous manual delineations of the prostate and the surrounding organs at risk are necessary for prostate cancer radiation therapy to avoid side effects to the latter. This process is time consuming and hampered by inter- and intraobserver variability, all of which could be alleviated by artificial intelligence (AI). This study aimed to evaluate the performance of AI compared with manual organ delineations on computed tomography (CT) scans for radiation treatment planning. Methods and Materials: Manual delineations of the prostate, urinary bladder, and rectum of 1530 patients with prostate cancer who received curative radiation therapy from 2006 to 2018 were included. Approximately 50% of those CT scans were used as a training set, 25% as a validation set, and 25% as a test set. Patients with hip prostheses were excluded because of metal artifacts. After training and fine-tuning with the validation set, automated delineations of the prostate and organs at risk were obtained for the test set. Sørensen-Dice similarity coefficient, mean surface distance, and Hausdorff distance were used to evaluate the agreement between the manual and automated delineations. Results: The median Sørensen-Dice similarity coefficient between the manual and AI delineations was 0.82, 0.95, and 0.88 for the prostate, urinary bladder, and rectum, respectively. The median mean surface distance and Hausdorff distance were 1.7 and 9.2 mm for the prostate, 0.7 and 6.7 mm for the urinary bladder, and 1.1 and 13.5 mm for the rectum, respectively. Conclusions: Automated CT-based organ delineation for prostate cancer radiation treatment planning is feasible and shows good agreement with manually performed contouring.

N-methyl-D-aspartate (NMDA)receptors (NMDARs) located on peripheral terminals of primary afferents are involved in the transduction of noxious mechanical stimuli. Exploiting the fact that both NMDARs and stretch-activated channels are retained in short-term culture and expressed on the soma of dorsal root ganglia (DRG) neurons, we examined the effect of NMDA on mechanically mediated changes in intracellular calcium concentration ([Ca2+]i). Our aims were to determine whether NMDARs modulate the mechanosensitivity of DRG neurons. Primary cultures of adult rat lumbosacral DRG cells were cultured for 1-3 days. [Ca2+]i responses were determined by Fura-2 ratio fluorescence. Somas were mechanically stimulated with fire-polished glass pipettes that depressed the cell membrane for 0.5 s. Voltage-activated inward Ca2+ currents were measured by the whole cell patch clamp. Stimulation of neurons with 100 microM NMDA in the presence, but not the absence, of co-agonist (10 microM D-serine) caused transient [Ca2+]i responses (101+/-9 nM) and potentiated [Ca2+]i peak responses to subsequent mechanical stimulation more than two-fold (P < 0.001). NMDA-mediated potentiation of mechanically induced [Ca2+]i responses was inhibited by the selective protein kinase C (PKC) inhibitor GF109203X (GFX; 10 microM), which had no independent effects on NMDA- or mechanically induced responses. Short-term treatment with the PKC activator phorbol dibutyrate (1 microM PDBu for 1-2 min) also potentiated mechanically induced [Ca2+]i responses nearly two-fold (P < 0.001), while longer exposure (>10 min) inhibited the [Ca2+]i transients by 44% (P < 0.001). Both effects of PDBu were prevented by prior treatment with GFX. Inhibition of voltage-dependent Ca2+ channels with 25 microM La3+ had no effect on mechanically induced [Ca2+]i transients prior to NMDA, but prevented enhancement of the transients by NMDA and PDBu. NMDA pretreatment transiently enhanced nifedipine-sensitive, voltage-activated Ca2+ currents by a process that was sensitive to GFX. In conclusion, activation of NMDARs on cultured DRG neurons sensitize voltage-dependent L-type Ca2+ channels which contribute to mechanically induced [Ca2+]i transients through a PKC-mediated process.

OBJECTIVE:To estimate the long-term risks of severe late toxicities for radiation therapy (RT) following radical prostatectomy (RP) in an unselected nationwide cohort, as severe side-effects are rare but may occur years later.PATIENTS AND METHODS:The study population comprised all men undergoing RP between 1997 and 2016 in the Prostate Cancer database Sweden (PCBaSe) (n = 40 962). By (1:2) matching, two cohorts were created: 2789 men exposed to postoperative RT and 5578 unexposed men with comparable age, comorbidities, and year of surgery. Cumulative incidences and rate ratios were calculated for the following outcomes: symptoms and interventions of the urinary or intestinal tract demanding inpatient care, secondary malignancies, and non-prostate cancer mortality.RESULTS:The largest differences were seen for late toxicities affecting the urinary tract. The 10-year cumulative incidences among those exposed to postoperative RT vs the RP-only group were: 17.8% vs 10.5% for procedures of the urinary tract (difference 7.3%, 95% confidence interval [CI] 4.4 to 10.3; relative risk [RR] 1.74, 95% CI 1.47 to 2.05); 6.0% vs 1.2% for haematuria (difference 4.8%, 95% CI 3.1 to 6.5; RR 6.50, 95% CI 4.31 to 10.10); and 2.4% vs 1.1% for bladder cancer (difference 1.4%, 95% CI 0.4 to 2.3; RR 2.71, 95% CI 1.72 to 4.33). The groups were similar regarding intestinal toxicity, other secondary malignancies, and non-prostate cancer mortality. Adjustments for preoperative tumour risk factors did not importantly affect the rate ratios.CONCLUSION:Severe late toxicity after postoperative RT following RP predominately affects the bladder and can appear many years after RT.

TPS192 Background: Radiotherapy of the primary tumor in metastatic prostate cancer is life-prolonging in patients with limited disease spread. Several different fractionation schedules have been used, most widely used is a four-week schedule of 2.75-3 Gy in 19-20 fractions. More data is emerging around hypo-fractionated radiotherapy in the curative setting. We hypothesize that a modified version of the Scandinavian Hypo-trial fractionation 6.1Gy per fraction x 6 fractions over a span of 2½ week will be non-inferior in side-effects as a 4-week schedule but more convenient for patients and caregivers. Methods: The Hypo-M1 trial is a randomized, stratified, multi-center, phase 3 clinical trial recruiting 420 patients in 9 Swedish centers. Key eligibility criteria include histological confirmed prostate cancer, indication for radiotherapy of low burden metastatic prostate cancer, defined as a max of 4 skeletal metastases at any site or lymph node metastases outside the pelvis and no other diseases or treatments interfering with radiotherapy or a score > 20 on the International prostate symptom score (IPSS) scale. Patients will be randomized to either 3 Gy x 19 or 6.1Gy x 6. Stratification factors are T1-T3 vs T4 and randomizing centre. Type of staging procedures performed, CT and whole-body bone scan is recommended, PSMA-PET allowed and further treatment beyond ADT is recorded but not stratification variables. Standard treatment may include docetaxel, apalutamide, abiraterone and enzalutamide at the treating physician’s discretion. Toxicity will be measured before, at the end of radiotherapy and at 1, 3, 6, 12 months and at 3 years. Measures used are the CTCAE v 5.0 and RTOG scales and QoL life will be measured at the same time points with the Prostate Cancer Symptom Scale (PCSS), a validated QoL instrument focusing on prostate cancer radiotherapy. The primary endpoint is QoL at 3 months and key secondary is acute toxicity at 3 months, late toxicity and QoL at 12 months, failure free survival and cause specific survival. The sample size is calculated for a continuous outcome non-inferiority trial with a one-sided alpha-value of 2.5 % and a beta-value of 80 %. The non-inferiority limit is set to 7.5 % This will require 175 patients with complete follow up in each treatment arm. Expecting a response rate of 80 % for the PCSS at the main time end point the total number of patients in each arm will be 210. The National Prostate Cancer Registry, covering 98% of all prostate cancer cases in Sweden, will be used as CRF including also a randomization module, making this a truly population based clinical trial. As of October 12, 2021, accrual is set to begin in December. The Hypo-M1 trial is an investigator-led, academic trial sponsored by the Swedish Society of Urological Oncology with study coordination provided by Cancer Center of Umeå University Hospital, Umeå, Sweden. Clinical trial information: NCT04612907.

OBJECTIVE:There is now an unprecedented amount of evidence to consider when revising prostate cancer guidelines. We believe that there is a value in publishing summaries of national clinical guidelines in English for others to read and comment on.METHODS:This is part 1 of a summary of the Swedish prostate cancer guidelines that were published in June 2022. It covers the early detection, diagnostics, staging, patient support and management of the non-metastatic disease. Part 2 covers recurrence after local treatment and management of the metastatic disease.RESULTS:The 2022 Swedish guidelines include several new recommendations: rectal iodine-povidone to reduce post-biopsy infections, external beam radiation with focal boost to the tumour, use of a pre-rectal spacer to reduce rectal side effects after external beam radiotherapy in some expert centres, 6 months' concomitant and adjuvant rather than neoadjuvant and concomitant hormonal treatment together with radiotherapy for unfavourable intermediate and high-risk disease, and adjuvant abiraterone plus prednisolone together with a GnRH agonist for a subgroup of men with very high-risk disease. The Swedish guidelines differ from the European by having more restrictive recommendations regarding genetic testing and pelvic lymph node dissection, the risk group classification, recommending ultra-hypofractionated (7 fractions) external radiotherapy for intermediate and selected high-risk cancers, by not recommending any hormonal treatment together with radiotherapy for favourable intermediate-risk disease, and by recommending bicalutamide monotherapy instead of a GnRH agonist for some patient groups.CONCLUSIONS:The 2022 Swedish prostate cancer guidelines include several new recommendations and some that differ from the European guidelines.

The aim of this study was to analyze the required absorbed doses to detectable metastases (Dreq) when using radionuclides with prostate specific membrane antigen (PSMA)-targeting radioligands to achieve a high probability for metastatic control. The Monte Carlo based analysis was performed for the clinically-used radionuclides yttrium-90, iodine-131, lutetium-177, and actinium-225, and the newly-proposed low-energy electron emitter terbium-161. It was demonstrated that metastatic formation rate highly influenced the metastatic distribution. Lower values generated few large detectable metastases, as in the case with oligo metastases, while high values generated a distribution of multiple small detectable metastases, as observed in patients with diffused visualized metastases. With equal number of detectable metastases, the total metastatic volume burden was 4–6 times higher in the oligo metastatic scenario compared to the diffusely visualized scenario. The Dreq was around 30% higher for the situations with 20 detectable metastases compared to one detectable metastasis. The Dreq for iodine-131 and yttrium-90 was high (920–3300 Gy). The Dreq for lutetium-177 was between 560 and 780 Gy and considerably lower Dreq were obtained for actinium-225 and terbium-161, with 240–330 Gy and 210–280 Gy, respectively. In conclusion, the simulations demonstrated that terbium-161 has the potential for being a more effective targeted radionuclide therapy for metastases using PSMA ligands.

BACKGROUND:The HYPO-RT-PC trial compared conventionally fractionated radiotherapy with ultra-hypofractionated radiotherapy in patients with localised prostate cancer. Ultra-hypofractionation was non-inferior to conventional fractionation regarding 5-year failure-free survival and toxicity. We aimed to assess whether patient-reported quality of life (QOL) differs between conventional fractionation and ultra-hypofractionation up to 6 years after treatment in the HYPO-RT-PC trial. METHODS:HYPO-RT-PC is a multicentre, open-label, randomised, controlled, non-inferiority, phase 3 trial done in 12 centres (seven university hospitals and five county hospitals) in Sweden and Denmark. Inclusion criteria were histologically verified intermediate-to-high-risk prostate cancer (defined as T1c-T3a with one or two of the following risk factors: stage T3a; Gleason score ≥7; and prostate-specific antigen 10-20 ng/mL with no evidence of lymph node involvement or distant metastases), age up to 75 years, and WHO performance status 0-2. Participants were randomly assigned (1:1) to conventional fractionation (78·0 Gy in 39 fractions, 5 days per week for 8 weeks) or ultra-hypofractionation (42·7 Gy in seven fractions, 3 days per week for 2·5 weeks) via a minimisation algorithm with stratification by trial centre, T-stage, Gleason score, and prostate-specific antigen. QOL was measured using the validated Prostate Cancer Symptom Scale (PCSS) and European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire (EORTC QLQ-C30) at baseline, the end of radiotherapy, months 3, 6, 12, and 24 after radiotherapy, every other year thereafter up to 10 years, and at 15 years. The primary endpoint (failure-free survival) has been reported elsewhere. Here we report QOL, a secondary endpoint analysed in the per-protocol population, up to 6 years after radiotherapy. The HYPO-RT-PC trial is registered with the ISRCTN registry, ISRCTN45905321. FINDINGS:Between July 1, 2005, and Nov 4, 2015, 1200 patients were enrolled and 1180 were randomly assigned (conventional fractionation n=591, ultra-hypofractionation n=589); 1165 patients (conventional fractionation n=582, ultra-hypofractionation n=583) were included in this QOL analysis. 158 (71%) of 223 patients in the conventional fractionation group and 146 (66%) of 220 in the ultra-hypofractionation group completed questionnaires at 6 years. The median follow-up was 48 months (IQR 25-72). In seven of ten bowel symptoms or problems the proportion of patients with clinically relevant deteriorations at the end of radiotherapy was significantly higher in the ultra-hypofractionation group than in the conventional fractionation group (stool frequency [p<0·0001], rush to toilet [p=0·0013], flatulence [p=0·0013], bowel cramp [p<0·0001], mucus [p=0·0014], blood in stool [p<0·0001], and limitation in daily activity [p=0·0014]). There were no statistically significant differences in the proportions of patients with clinically relevant acute urinary symptoms or problems (total 14 items) and sexual functioning between the two treatment groups at end of radiotherapy. Thereafter, there were no clinically relevant differences in urinary, bowel, or sexual functioning between the groups. At the 6-year follow-up there was no difference in the incidence of clinically relevant deterioration between the groups for overall urinary bother (43 [33%] of 132 for conventional fractionation vs 33 [28%] of 120 for ultra-hypofractionation; mean difference 5·1% [95% CI -4·4 to 14·6]; p=0·38), overall bowel bother (43 [33%] of 129 vs 34 [28%] of 123; 5·7% [-3·8 to 15·2]; p=0·33), overall sexual bother (75 [60%] of 126 vs 59 [50%] of 117; 9·1% [-1·4 to 19·6]; p=0·15), or global health/QOL (56 [42%] of 134 vs 46 [37%] of 125; 5·0% [-5·0 to 15·0]; p=0·41). INTERPRETATION:Although acute toxicity was higher for ultra-hypofractionation than conventional fractionation, this long-term patient-reported QOL analysis shows that ultra-hypofractionation was as well tolerated as conventional fractionation up to 6 years after completion of treatment. These findings support the use of ultra-hypofractionation radiotherapy for intermediate-to-high-risk prostate cancer. FUNDING:The Nordic Cancer Union, the Swedish Cancer Society, and the Swedish Research Council.