The theme for ESTRO 2025 was “Transformative Innovation Through Partnership,” emphasizing the importance of collaboration and partnership to push the boundaries of radiation oncology and multidisciplinary cancer care. The program featured interactive sessions, panel discussions, and joint sessions with partner associations, focusing on breakthrough research and innovation. The congress aimed to connect the radiotherapy community, highlight top-level scientific work, and foster collaboration between all stakeholders.
At Accuray, we introduced a powerful theme of our own: “Distinct in Every Way,” with three core pillars, Distinct by Outcomes, Distinct by Design and Distinct by Expertise. This theme underscores our unwavering commitment to excellence in radiotherapy; with a goal to ensure more patients receive precise and effective radiotherapy treatments.
Together, these themes represent a unified approach to advancing cancer treatment through innovative and collaborative efforts, highlighting the importance of working together to achieve superior outcomes in radiation oncology.
In this blog we take immense pride in showcasing some of the research presented at ESTRO 2025 by radiation oncologists, medical physicists, and therapeutic radiographers who use the Accuray CyberKnife®, TomoTherapy® and Radixact® Systems. Their dedication to advancing the field of radiotherapy exemplifies the transformative impact of our innovative technologies.
CyberKnife® System Research Highlights
Brain
Abstracts that focused on intracranial cases treated with the CyberKnife® System included brain metastases, glioblastoma and pituitary adenoma. One study found the CyberKnife System offered an effective treatment option for patients with primary tumors that rarely metastasize to the brain. A median dose of 20 Gy in a single fraction was delivered to 47 patients and a median overall survival (OS) of 89.9 months was recorded, demonstrating high local control rates.1
Another study reviewed 42 patients with two or more stereotactic radiosurgery (SRS) treatments to new brain metastasizes, finding acceptable rates of brain progression free survival and toxicity.2
A center in Spain treated 30 patients with pituitary adenoma post surgery with the CyberKnife System using 24-25 Gy in 3-5 fractions. With a median follow up of 26 months, no late toxicity was observed and all patients showed a radiological response or stability.3
A study conducted in Poland examined 78 patients diagnosed with glioblastoma, who required re-irradiation following an initial total dose of 60 Gy. These patients received an additional 10-16 Gy administered in 2 fractions, contingent upon the tumor’s size and location. The progression-free survival for this cohort ranged from 3 to 24 months. The study concluded that stereotactic radiation therapy utilizing the CyberKnife System offered a valuable treatment option in these patients, offering good efficacy and low toxicities.4
Spine
Spine stereotactic body radiotherapy (SBRT) is becoming more widely available and there is increasing evidence for its use. A study of 119 patients treated with SBRT to the spine evaluated doses delivered to the spinal cord and the rate of radiation myelopathy. They found that no radiation myelopathy was seen in any patient at 18 months post SBRT. The use of intrafraction tracking with Synchrony® helped to give confidence that the dose was delivered as planned.5
Another retrospective study of 91 patients treated with spinal SBRT also found excellent local control with a low risk of vertebral compression fracture (VCF). An increased risk of VCF was associated in patients >70 years.6
A study conducted in Spain examined 61 patients who received spinal SBRT treatment. The study concluded that SBRT administered using the CyberKnife System was effective for managing spine metastases. They found the risk of VCF came at a higher risk in patients treated with a single fraction.7
Prostate
Many studies continue to demonstrate the benefits of SBRT to patients with low-intermediate and high-risk prostate cancer. Here are some highlights:
A retrospective study compared the CyberKnife System to low dose rate brachytherapy (LDR-BT). They reviewed 226 low- and intermediate-risk prostate cancer patients (119n = CyberKnife System and 107n = LDR-BT). Local relapse free survival was found to be significantly higher in the CyberKnife System group. Although more acute gastrointestinal (GI) side effects there was no significant difference when reviewing the late GI side effects. The 6-year outcome with the CyberKnife System were found to be similar or even better than with LDR-BT.8
Preliminary results of the PRO-FAST study were presented. This is prospective single-arm trial of urethral sparing HDR-like SBRT for prostate cancer patients. The first 12 patients were treated, including high-risk, unfavorable and favorable intermediate risk patients. No grade 3 toxicity was recorded in the first 12 patients which has allowed the study to continue recruiting more patients for this type of treatment. This treatment greatly benefits patients who have long distances to travel for treatment, allowing them to have treatment is just one day.9
Another prospective observational trial called PRO-SPEED evaluated acute and late genitourinary and gastrointestinal toxicities as well as biochemical and clinical outcomes in patients with localized prostate cancer treated with ultra-hypofractionated SBRT with a simultaneous integrated boost to the dominant intraprostatic lesions using the CyberKnife System. Thirty patients completed treatment receiving 36.25 Gy to the prostate and 40 Gy to the DIL over five fractions. Preliminary data to data demonstrated that this treatment was effective with low rates of GU and GI toxicities, excellent early biochemical and clinical control.10
A retrospective planning study compared radiation dose and treatment efficiency between the InciseTM Multileaf Collimator (MLC) and the Iris collimator with the CyberKnife System in prostate cancer patients. The preliminary results suggested advantages with the InCise MLC over the Iris collimator in terms of beam on time and monitor units. Dosimetric parameters were mainly comparable but further investigation is required to determine if the Iris collimator can offer superior dose minimization to OAR in certain patients. This study gives insights on the ideal collimator to use depending on specific patient cases.11
Liver
A retrospective study assessed local control and recurrence in patients receiving hepatic SBRT in more than 4 fractions due to dosimetric limits. Thirty-three patients, unsuitable for 3-4 fractions due to nearby OARs, were treated for hepatocellular carcinoma or liver metastases in more than 4 fractions. Despite dose reductions to protect OARs, SBRT achieved satisfactory local control with low toxicity. Prospective data is needed to confirm these findings.12
A study was conducted to assess the treatment outcomes for patients with malignant liver lesions who were treated using the CyberKnife System. The study included forty-one patients with 1-5 lesions, ranging in size from 0.8 to 6.5 cm. Treatment protocols varied from 3 to 12 fractions, with a total mean dose of 50.5 Gy. The OS rates at 1, 2, and 3 years were 92.5%, 88.9%, and 69%, respectively. With a mean follow-up period of 32.6 months, no late toxicities were observed. The authors concluded that robotic SBRT for liver lesions is an effective local treatment method, demonstrating high rates of local control and minimal acute toxicities.13
Oligometastases
A phase-II study evaluated 52 patients with abdominal lymph node metastases undergoing CT-guided, online adaptive SBRT to increase iso-toxic dose to the target. For each patient, three plans were created using pre-treatment CT scans: Standard of care plan, adaptive plan with OAR contours from a diagnostic CT, and an adaptive plan based on the planning CT. After a pre-fraction in-room CT scan, the radiation technologist selected the plan with the highest target coverage without exceeding OAR constraints. An adaptive plan was chosen in 58% of fractions and 78% of patients were treated with at least one adaptive plan; resulting in a significantly higher given GTV Dmean compared to the planned dose. The authors concluded that this workflow enabled a dose increase to the target and offers a chance of better oncological outcomes.14
A retrospective study analyzed outcomes and safety of robotic SBRT performed at a single institution for oligometastatic disease from gynecological tumors. Fifty-four patients were included in the study. A median dose of 40 Gy in 1-8 fractions was prescribed. Oligometastases were located in the lung, liver, lymph node, bone and brain. No acute grade 3 or higher toxicities were reported. The authors found using higher doses than in the MITO retrospective trials, they observed a high rate of local complete response and local relapse free survival. Patients with a complete response after SBRT demonstrated a significantly higher disease free survival compared to those with stable/partial response or progressive disease.15
Radixact® System Research Highlights
A study conducted in India assessed treatment outcomes for glioblastoma patients using three different modalities: 3DCRT, IMRT, and helical delivery via the TomoTherapy® System. This analysis included a total of 135 patients, with 45 patients treated under each modality, all receiving a dosage of 60 Gy in 30 fractions. Evaluations were carried out using MRI and DOPA-PET CT, comparing post-treatment results to pre-treatment values. The average tumor volume at one year post-treatment was found to be smaller in patients treated with helical delivery compared to those treated with 3DCRT or IMRT. The study indicated a higher frequency of infield recurrences with both 3DCRT and IMRT compared to helical delivery. Additionally, no marginal field recurrences were identified in patients treated with the TomoTherapy System. Consequently, helical delivery demonstrated superior performance relative to 3DCRT and IMRT, resulting in fewer recurrences among patients. The authors concluded that “helical TomoTherapy [System] is a superior modality of radiation therapy in glioblastoma, when compared to IMRT and 3DCRT, demonstrating greater tumor parameter reduction on imaging and a lower recurrence rate.”16
Breast
A single-center retrospective study conducted in France evaluated the efficacy, safety, clinical data, and survival outcomes of 179 non-metastatic breast cancer patients treated with the TomoTherapy System. The ten-year follow-up results demonstrated local recurrence-free survival at 95.3%, locoregional recurrence-free survival at 94.5%, metastasis-free survival at 82.9%, disease-specific survival at 94.3%, and OS at 88%. Notably, there were no reports of grade 3 or higher acute or late toxicity, nor any radiation-induced late pulmonary or cardiac toxicity. The authors concluded that helical delivery using the TomoTherapy System is an effective technique for the treatment of breast cancer, citing low recurrence rates and good treatment tolerance.17
Another study from France evaluated the performance of the VitalHoldTM solution for automated deep inspiration breath hold (DIBH) on the Radixact® System, focusing on dosimetry accuracy and responsiveness in respiratory motion. The authors found that the VitalHold module on the Radixact System demonstrates strong potential for automated DIBH treatment, providing precise and reliable beam control under simulated breath-hold conditions, particularly for gating tolerances of 2 to 5 mm. This study supports the integration of automated breath-hold techniques in clinical practice.18
For more information you can read the published article Automated Deep Inspiration Breath-Hold (DIBH) in breast radiotherapy: A comprehensive assessment of the VitalHold system on the Radixact platform
Lung
A single center in Turkey reported on the short-term clinical outcomes of lung cancer patients treated with SBRT. Thirteen patients with lung metastases, seven with central tumors and six with peripheral tumors, were treated using Synchrony real-time adaptive delivery on the Radixact System. Simulation scans were acquired to assess treatment needs. Over a median follow-up of six months, there was a 100% local control rate with no toxicity. The authors conclude that Synchrony real-time motion tracking is precise and effective for lung SBRT in selected patients.19
Gynecological
A prospective descriptive study assessed survival rates and toxicity in 44 advanced cervical cancer patients treated with helical IMRT using the TomoTherapy System. The treatment included helical IMRT, high dose rate brachytherapy, and concurrent chemotherapy. At 36 months follow-up, local and regional recurrence free survival was 88.6%, while metastatic recurrence free survival was 95.5%. Acute grade 3 hematological toxicity occurred in 25% of patients, with few experiencing late grade 3 proctitis (3%) or urethral stricture (1%). The authors concluded that helical IMRT is effective for advanced cervical cancer treatment.20
Urology
A prospective study reported toxicity and biochemical control in 68 localized and locally advanced prostate cancer patients treated with helical IMRT using a simultaneous integrated boost (SIB-HIMRT) using the TomoTherapy System. A total dose of 67.5 Gy in 25 fractions was delivered. Acute genitourinary (GU) toxicity grade 2 or higher was observed in 13% patients, while gastrointestinal (GI) grade 2 or higher was reported in 7% patients. No patients experienced grade 3 acute toxicity. Late GU and GI toxicities of grade 2 or higher were observed in 12% and 4% patients, respectively. There were no cases of local, regional or distant failure at last follow up. The authors concluded that they observed a positive outcome of toxicity in all patients.21
A retrospective, descriptive, analytical study was conducted involving 13 patients diagnosed with stage II-IV muscle invasive bladder cancer. The purpose of the study was to evaluate the toxicity and efficacy of immunotherapy combined with external beam radiotherapy as part of the INMUNOPRSEVE trial. Participants were administered durvalumab and tremelimumab in conjunction with 46 Gy to the pelvis and 60-64 Gy to the bladder, utilizing helical IGRT on the TomoTherapy System. The median progression-free survival was recorded at 39.3 months, while the median OS was 41.9 months. The authors observed promising survival outcomes with a minimal incidence of acute and chronic toxicity.22
Accuray thanks all the health care professionals for their contributions to research that help improve patient care.
References
- Senay Mutaf. (2025) ‘Stereotactic radiosurgery of brain metastases from cancers that rarely metastasize to the central nervous system’. Poster 2604. ESTRO
- Ignacio Maria Gomez Paloma et al. (2025) ‘Consecutive radiosurgery for multiple brain metastases with CyberKnife Robotic Radiosurgery Unit: Outcomes and Predictive Factors at a Hospital Center’. Poster 4246. ESTRO
- Julen Azcona Martin et al. (2025) ‘Hypofractionated radiosurgery for functioning and non-functioning pituitary adenomas after surgery: Our working experience with Cyberknife unit.’ Poster 4071. ESTRO
- Hanna Grzbiela et al. ‘The efficacy of CyberKnife® stereotactic radiation therapy in re-irradiation of recurrent glioblastoma.’ Poster 4197. ESTRO
- Timothy Jackson et al. (2025) ‘A review of 130 CyberKnife spinal metastasis SABR treatments at one centre to assess risk of spinal cord toxicity.’ Poster 1417. ESTRO
- Binnaz Yasar et al. (2025) ‘A single institution study of efficacy and toxicity outcomes of spinal SBRT in prostate cancer.’ Poster 3039. ESTRO
- Adrian Durango Mendez et al. ‘Use of Stereotactic Body Radiotherapy (SBRT) for Spine Metastases with Robotic Radiosurgery Unit.’ Poster 3732. ESTRO
- Péter Ágoston et al. (2025) Comparison of radiotherapy with CyberKnife or low dose rate brachytherapy of low-intermediate risk prostate cancer patients after six-year follow-up.’ Poster 2803. ESTRO
- Andrei Fodor et al. (2025) ‘One-day urethral-sparing, HDR-like, prostate cancer robotic SBRT: preliminary results of the PRO-FAST trial.’ Poster 3898.ESTRO
- Giovanni Carlo Mazzolae et al. (2025) ‘CyberKnife UH-SBRT for localized prostate cancer and DIL: preliminary report of acute and late toxicity of the PRO-SPEED trial (NCT06331013).’ Poster 3492. ESTRO
- Gaetano Gagliardo et al. ‘Analysis and comparison of CyberKnife MLC collimator versus IRIS collimator in prostate SBRT.’ Poster 3734. ESTRO
- Alizee Renan et al. (2025) ‘Liver SBRT in more than 4 fractions: local control and recurrence patterns.’ Poster 540. ESTRO
- Ahmed Abdelmaqsoud et al. (2025) ‘Robotic stereotactic body radiotherapy for malignant liver lesions: Local control and overall survival – a Monoinstitutional study’. Poster 2454. ESTRO
- Lucy A. van Werkhoven et al. ‘Increased iso-toxic dose to the target in oligometastatic abdominal lymph nodes using CT-guided online adaptive SBRT.’ Poster 2332. ESTRO
- Gaia Parma et al. (2025) ‘Higher disease-free survival observed for complete response after SBRT in oligometastatic gynecologic tumors.’ Poster 3605. ESTRO
- Sweetruti Hegde et al. (2025) ‘Comparative analysis of 3DCRT, IMRT and Helical Tomotherapy in Glioblastoma: Evaluation of recurrence dynamics.’ Poster 67. ESTRO
- Abdelkarim Uakkas et al. (2025) ‘Long-term follow-up results of helical tomotherapy for non-metastatic breast cancer: single center experience.’ Poster 3750. ESTRO
- Paul Retif et al. ‘Automated Deep Inspiration Breath-Hold (DIBH) in Breast Radiotherapy: A Comprehensive Assessment of the VitalHold System on the Radixact Platform.’ Poster 2412. ESTRO
- Evren Ozan Goksel et al. ‘Initial Experience and Short-Term Clinical Outcomes of Lung cancer Patients Treated with SBRT Using the Radixact Synchrony Tumor Tracking System.’ Poster 4043. ESTRO
- Sofiane Mellouk (2025) ‘IMRT by TomoTherapy with concurrent weekly cisplatin followed by Brachytherapy HDR in locally advance cervical cancer (prospective study).’ Poster 447. ESTRO
- Cheikh Tayer et al. (2025) ‘Early report on acute and late toxicity of Helical Intensity Modulated Radiation Therapy with Simultaneous Integrated Boost for cancer prostate.’ Poster 3089. ESTRO
- Isabela Gaztelu et al. (2025) ‘Bladder Preservation Using Immunotherapy and Radiotherapy in Muscle-Invasive Bladder Cancer.’ Poster 2849. ESTRO
