Aims: To present the preliminary results on the clinical utilisation of an online daily adaptive magnetic resonance-guided radiation therapy (MRgRT) for various gynaecological cancers. Materials and methods: Twelve patients treated between September 2018 and June 2022 were included. Six patients (50%) were treated with pelvic radiation therapy followed by MRgRT boost as brachytherapy boost was ineligible or unavailable, three patients (25%) were treated with pelvic MRgRT followed by high dose rate brachytherapy, two patients (16.7%) were treated with only MRgRT, one patient (8.3%) was treated with linear accelerator-based radiation therapy followed by MRgRT boost for bulky iliac lymph nodes. Results: The median age was 56.5 years (range 31-86 years). Eight patients (66.7%) had a complete response, three patients (25%) had a partial response and one patient (8.3%) died due to acute renal failure. The mean follow-up time was 11.2 months (range 3.1-42.6 months). The estimated 1-year overall survival was 88.9%. The median treatment time was 47 days (range 10-87 days). During external beam radiation therapy, 10 (83.3%) patients had concomitant chemoradiotherapy. Pelvic external beam radiation therapy doses for all cohorts were 45-50.4 Gy with a fraction dose of 1.8 Gy. The median magnetic resonance-guided boost dose was 32 Gy (range 20-50 Gy) and fraction doses ranged between 4 and 10 Gy. Three patients were treated with intracavitary high dose rate brachytherapy (26-28 Gy in four to five fractions). None of the patients had grade >3 late genitourinary toxicities. Conclusion: MRgRT is reliable and clinically feasible for treating patients with gynaecological cancers alone or in combination with brachytherapy with an acceptable toxicity and outcome. MRgRT boost could be an option when brachytherapy is not available or ineligible. (c) 2023 Published by Elsevier Ltd on behalf of The Royal College of Radiologists.

H3K27 altered pediatric pontine diffuse midline gliomas (pDMG) have a poor prognosis, and conventional treatments offer limited benefits. However, recent advancements in molecular evaluations and targeted therapies have shown promise. The aim of this retrospective analysis was to evaluate the effectiveness of German-sourced ONC201, a selective antagonist of dopamine receptor DRD2, for the treatment of pediatric H3K27 altered pDMGs. Pediatric patients with H3K27 altered pDMG treated between January 2016 and July 2022 were included in this retrospective analysis. Tissue samples were acquired from all patients via stereotactic biopsy for immunohistochemistry and molecular profiling. All patients received radiation treatment with concurrent temozolomide, and those who could acquire GsONC201 received it as a single agent until progression. Patients who could not obtain GsONC201 received other chemotherapy protocols. Among 27 patients with a median age of 5.6 years old (range 3.4–17.9), 18 received GsONC201. During the follow-up period, 16 patients (59.3

Endometrial carcinoma is the most frequently diagnosed gynecological cancer among women aged 50 and older in developed countries. In patients who are not amenable to surgery, radiotherapy results in improved survival with acceptable adverse effect profiles. Definitive stereotactic body radiotherapy (SBRT) as a monotherapy remains an unaddressed concept in the literature. Here, we present the case of an 86-year-old woman who was diagnosed with early-stage endometrial carcinoma and was medically inoperable due to cardiac comorbidities. She was treated with magnetic resonance imaging-guided online adaptive radiotherapy-based SBRT. She tolerated the treatment well, with mild increased vaginal discharge. Complete metabolic and radiological responses were obtained. She continues to be disease free in the first year of treatment with no long-term side effects. Our protocol presents promising results with a safe toxicity profile for inoperable early-stage endometrial cancer. Future studies are warranted in light of the current knowledge.

Colorectal cancer is the third most common cancer in Turkey. The current guidelines do not provide sufficient information to cover all aspects of the management of rectal cancer. Although treatment has been standardized in terms of the basic principles of neoadjuvant, surgical, and adjuvant therapy, uncertainties in the management of rectal cancer may lead to significant differences in clinical practice. In order to clarify these uncertainties, a consensus program was constructed with the participation of the physicians from the Acıbadem Mehmet Ali Aydınlar and Koç Universities. This program included the physicians from the departments of general surgery, gastroenterology, pathology, radiology, nuclear medicine, medical oncology, radiation oncology, and medical genetics. The gray zones in the management of rectal cancer were determined by reviewing the evidence-based data and current guidelines before the meeting. Topics to be discussed consisted of diagnosis, staging, surgical treatment for the primary disease, use of neoadjuvant and adjuvant treatment, management of recurrent disease, screening, follow-up, and genetic counseling. All those topics were discussed under supervision of a presenter and a chair with active participation of related physicians. The consensus text was structured by centralizing the decisions based on the existing data.

Abstract Background The ESTRO-ACROP Consensus Guideline (EACG) recommends implant excluded clinical target volume (CTVp) definitions for post-mastectomy radiation therapy after implant-based immediate breast reconstruction (IBR). The purpose of this study is to investigate the effectiveness of Helical Tomotherapy (HTp) and Volumetric Modulated Arc Therapy (VMATp) treatment techniques in terms of CTVp coverage and reduced organ at risk (OAR), normal tissue and implant doses when CTVp was used for treatment planning as the target structure instead of conventional CTV. Methods Eight left-sided and eight right-sided breast cancer patients who underwent IBR after mastectomy were included in this study. Planning CT data sets were acquired during free breathing and patients were treated with HT technique targeted to conventional CTV. Retrospectively, CTVp was delineated based on EACG by the same radiation oncologist, and treatment plans with HTp and VMATp techniques were generated based on CTVp. For each patient, relevant dosimetric parameters were obtained from three different treatment plans. Results There was no statistically significant difference on target coverage in terms of, PTVp-D95, PTVp-Vpres, homogeneity index (p > 0.05) between HTp and VMATp plans. But, the conformity numbers were significantly higher (HTp vs VMATp, 0.69 ± 0.15 vs 0.79 ± 0.12) for VMATp (Z = − 2.17, p = 0.030). While HTp significantly lowered Dmax and Dmean for LAD (LAD-Dmax: χ2 = 12.25, p = 0.002 and LAD-Dmean: χ2 = 12.30, p = 0.002), neither HTp nor VMATp could reduce maximum and mean dose to heart (p > 0.05). Furthermore, heart volume receiving 5 Gy was significantly higher for VMATp when compared to HTp (21.2 ± 9.8 vs 42.7 ± 24.8, p: 0.004). Both techniques succeeded in reducing the mean dose to implant (HTp vs HT, p < 0.001; VMATp vs HT, p < 0.001; VMATp vs HTp, p = 0.005). Conclusion Both HTp and VMATp techniques succeeded to obtain conformal and homogeneous dose distributions within CTVp while reducing the mean implant dose. HTp was found to be superior to VMATp with regards to lowering all OAR doses except for CB.

Objective: Using moderate or ultra-hypofractionation, which is also known as stereotactic body radiotherapy (SBRT) for treatment of localized prostate cancer patients has been increased. We present our preliminary results on the clinical utilization of MRI-guided adaptive radiotherapy (MRgRT) for prostate cancer patients with the workflow, dosimetric parameters, toxicities and prostate-specific antigen (PSA) response. Methods: 50 prostate cancer patients treated with ultra-hypofractionation were included in the study. Treatment was performed with intensity-modulated radiation therapy (step and shoot) technique and daily plan adaptation using MRgRT. The SBRT consisted of 36.25 Gy in 5 fractions with a 7.25 Gy fraction size. The time for workflow steps was documented. Patients were followed for the acute and late toxicities and PSA response. Results: The median follow-up for our cohort was 10 months (range between 3 and 29 months). The median age was 73.5 years (range between 50 and 84 years). MRgRT was well tolerated by all patients. Acute genitourinary (GU) toxicity rate of Grade 1 and Grade 2 was 28 and 36%, respectively. Only 6% of patients had acute Grade 1 gastrointestinal (GI) toxicity and there was no Grade ≥ 2 GI toxicity. To date, late Grade 1 GU toxicity was experienced by 24% of patients, 2% of patients experienced Grade 2 GU toxicity and 6% of patients reported Grade 2 GI toxicity. Due to the short follow-up, PSA nadir has not been reached yet in our cohort. Conclusion: In conclusion, MRgRT represents a new method for delivering SBRT with markerless soft tissue visualization, online adaptive planning and real-time tracking. Our study suggests that ultra-hypofractionation has an acceptable acute and very low late toxicity profile. Advances in knowledge: MRgRT represents a new markerless method for delivering SBRT for localized prostate cancer providing online adaptive planning and real-time tracking and acute and late toxicity profile is acceptable.

Purpose: We aimed to present our initial clinical experience on the implementation of a stereotactic MR-guided online adaptive radiation therapy (SMART) for the treatment of liver metastases in oligometastatic disease. Materials and Methods: Twenty-one patients (24 lesions) with liver metastasis treated with SMART were included in this retrospective study. Step-and-shoot intensity-modulated radiotherapy technique was used with daily plan adaptation. During delivery, real-time imaging was used by acquiring planar magnetic resonance images in sagittal plane for monitoring and gating. Acute and late toxicities were recorded both during treatment and follow-up visits. Results: The median follow-up time was 11.6 months (range, 2.2 to 24.6 months). The median delivered total dose was 50 Gy (range, 40 to 60 Gy); with a median fraction number of 5 (range, 3 to 8 fractions) and the median fraction dose was 10 Gy (range, 7.5 to 18 Gy). Ninety-three fractions (83.7%) among 111 fractions were re-optimized. No patients were lost to follow-up and all patients were alive except one at the time of analysis. All of the patients had either complete (80.9%) or partial (19.1%) response at irradiated sites. Estimated 1-year overall survival was 93.3%. Intrahepatic and extrahepatic progression-free survival was 89.7% and 73.5% at 1 year, respectively. There was no grade 3 or higher acute or late toxicities experienced during the treatment and follow-up course. Conclusion: SMART represents a new, noninvasive and effective alternative to current ablative radiotherapy methods for treatment of liver metastases in oligometastatic disease with the advantages of better visualization of soft tissue, real-time tumor tracking and potentially reduced toxicity to organs at risk.

Purpose: To present the radiation therapy quality assurance results from a prospective multicenter phase 2 randomized trial of short versus protracted urethra-sparing stereotactic body radiation therapy (SBRT) for localized prostate cancer. Methods and Materials: Between 2012 and 2015, 165 patients with prostate cancer from 9 centers were randomized and treated with SBRT delivered either every other day (armA, n=82) or once aweek (armB, n=83); 36.25Gy in 5 fractionswere prescribed to the prostate with (n = 92) or without (n = 73) inclusion of the seminal vesicles (SV), and the urethra planning-risk volume received 32.5Gy. Patientswere treated either with volumetricmodulated arc therapy (VMAT; n=112) or with intensitymodulated radiation therapy (IMRT; n=53). Deviations from protocol dose constraints, planning target volume (PTV) homogeneity index, PTV Dice similarity coefficient, and number of monitor units for each treatment plan were retrospectively analyzed. Dosimetric results of VMAT versus IMRT and treatment plans with versus without inclusion of SV were compared. Results: At least 1 major protocol deviation occurred in 51 patients (31%), whereas none was observed in 41. Protocol violations were more frequent in the IMRT group (P < .001). Furthermore, the use of VMAT yielded better dosimetric results than IMRT for urethra planning-risk volume D-98%(31.1 vs 30.8Gy, P<.0001), PTVD2% (37.9 vs 38.7Gy, P<.0001), homogeneity index (0.09 vs 0.10, P <.0001), Dice similarity coefficient (0.83 vs 0.80, P <.0001), and bladder wall V-50% (24.5% vs 33.5%, P=.0001). To achieve its goals volumetric modulated arc therapy required fewer monitor units than IMRT (2275 vs 3378, P <.0001). The inclusion ofSVin the PTVnegatively affected the rectal wall V-90%(9.1% vs 10.4%, P=.0003) and V-80%(13.2% vs 15.7%, P=.0003). Conclusions: Protocol deviations with potential impact on tumor control or toxicity occurred in 31% of patients in this prospective clinical trial. Protocol deviations were more frequent with IMRT. Prospective radiation therapy quality assurance protocols should be strongly recommended for SBRT trials to minimize potential protocol deviations. (C) 2020 Elsevier Inc. All rights reserved.

AbstractBackgroundTo present the 18 months results from a prospective multicenter phase II randomized trial of short vs protracted urethra‐sparing stereotactic body radiotherapy (SBRT) for localized prostate cancer (PCa).MethodsBetween 2012 and 2015, a total of 170 PCa patients were randomized to 36.25 Gy in 5 fractions (6.5 Gy × 5 to the urethra) delivered either every other day (EOD, arm A, n = 84) or once a week (QW, arm B, n = 86). Genitourinary (GU) and gastrointestinal (GI) toxicity (CTCAE v4.0 scale), IPSS, and QoL scores were assessed at baseline, at the 5th fraction (5fx), 12th weeks (12W), and every 6 months after SBRT. The primary endpoint was biochemical control at 18 months and grade ≥ 3 toxicity (including grade ≥ 2 for urinary obstruction/retention) during the first 3 months.ResultsAmong the 165 patients analyzed, the toxicity stopping rule was never activated during the acute phase. Maximum acute grade 2 GU toxicity rates at 5fx were 17% and 19% for arms A and B, respectively, with only 2 cases of grade 2 GI toxicity at 5fx in arm A. At month 18, grade ≥ 2 GU and GI toxicity decreased below 5% and 2% for both arms. No changes in EORTC QLQ‐PR25 scores for GU, GI, and sexual domains were observed in both arms between baseline and month 18. Four biochemical failures were observed, 2 in each arm, rejecting the null hypothesis of an unfavorable response rate ≤ 85% in favor of an acceptable ≥ 95% rate.ConclusionsAt 18 months, urethra‐sparing SBRT showed a low toxicity profile, with minimal impact on QoL and favorable biochemical control rates, regardless of overall treatment time (EOD vs QW).

Extreme hypofractionation by use of SBRT is being frequently used in localized prostate cancer (Pca), after the early studies have resulted in favorable outcome and acceptable toxicity. Stereotactic MR-guided Adaptive Radiotherapy (SMART) has the advantages for markerless, MR guidance with daily adaptation and smaller PTV margins. We aimed to report our initial experience with SMART in localized Pca. Between 09/18-10/19, 35 consecutive patients with T1c-T3aN0M0 Pca were treated with MRidian MRLINAC (ViewRay, OH). Risk groups were low in 20%, intermediate in 57% and high in 23%. MR and CT simulation was done after 3 hours of fasting, fleet enema and 40 mins after 250 cc water. Isotropic PTV margin was 3 mm over CTV (prostate+/-seminal vesicles). Static IMRT plans to give 3625 cGy/5 fractions were studied. 26% received androgen ablation. All patients were treated every other day. Median follow up time was 7 (Range: 1-14) months. Plan adaptation was done in 74% of 175 fractions. The reasons for plan adaptation were target volume coverage in 38%, OAR violation in 26% and both in 32%. Overall treatment time was median 45 min (29-95 min, range). Acute GU toxicity was seen in 34% as Gr1 and in 11% as Gr2. GI toxicity was seen as Gr 1 in 6%. Alpha blocker was needed during treatment for urinary symptoms in 23% of patients. No grade 3 or higher acute or late toxicity was observed. Early PSA kinetics after treatment were positive as expected from SBRT. Only 1 high risk patient developed systemic metastasis and another patient developed biochemical failure. SMART is a tolerable and convenient markerless treatment method for localized Pca patients. Our early results support low toxicity with high rate of local control.

OBJECTIVE:We identified factors influencing outcomes in patients with medically inoperable early stage lung cancer (MIESLC) treated with stereotactic ablative radiation therapy (SABR) at 14 centers in Turkey. MATERIALS AND METHODS:We retrospectively analyzed 431 patients with stage I-II MIESLC treated with SABR from 2009 through 2017. Age; sex; performance score; imaging technique; tumor histology and size; disease stage radiation dose, fraction and biologically effective dose with an α/β ratio of 10 (BED10 ); tumor location and treatment center were evaluated for associations with overall survival (OS), local control (LC) and toxicity. RESULTS:Median follow-up time was 27 months (range 1-115); median SABR dose was 54 Gy (range 30-70) given in a median three fractions (range 1-10); median BED10 was 151 Gy (range 48-180). Tumors were peripheral in 285 patients (66.1%), central in 69 (16%) and <1 cm from mediastinal structures in 77 (17.9%). Response was evaluated with PET/CT in most cases at a median 3 months after SABR. Response rates were: 48% complete, 36.7% partial, 7.9% stable and 7.4% progression. LC rates were 97.1% at 1 year, 92.6% at 2 years and 91.2% at 3 years; corresponding OS rates were 92.6%, 80.6% and 72.7%. On multivariate analysis, BED10 > 100 Gy (P = .011), adenocarcinoma (P = .025) and complete response on first evaluation (P = .007) predicted favorable LC. BED10 > 120 Gy (hazard ratio [HR] 1.9, 95% confidence interval [CI] 1.1-3.2, P = .019) and tumor size (<2 cm HR 1.9, 95% CI 1.3-3, P = .003) predicted favorable OS. No grade 4-5 acute side effects were observed; late effects were grade ≤3 pneumonitis (18 [4.2%]), chest wall pain (11 [2.5%]) and rib fracture (1 [0.2%]). CONCLUSION:SABR produced encouraging results, with satisfactory LC and OS and minimal toxicity. BED10 > 120 Gy was needed for better LC and OS for large, non-adenocarcinoma tumors.

Posterior fossa ependymomas (PFE) are the third most common posterior fossa tumors in childhood and are a major cause of morbidity and mortality despite multimodality treatments. Recent molecular studies have grouped them to two distinct entities (PFA and PFB) by using H3K27me3 expression. PFA group is seen in infants and younger childhood and has poor prognosis, while PFB group is seen in older population with a better prognosis. In this study we aimed to investigate the treatment outcomes according to newly defined molecular subtypes and assess the role of previously known prognostic factors within these PFE groups. Forty-two consecutive patients operated for PFE between 1996-2018 were retrospectively investigated. Until 2009 patients >3 years received adjuvant radiotherapy (RT), whereas after 2009 the age threshold was decreased to 2 years. Patients with localized disease were given local RT, patients with spinal seeding received craniospinal RT. Adjuvant chemotherapy (CT) were given to patients with anaplastic pathology, residual disease, spinal seeding or infants who didn't receive RT. All pathology blocks were reviewed and H3K27me3 was assessed with immunohistochemistry for molecular grouping. Median age was 32 months (8-172 m, range), female/male ratio 20/22. Resection was gross total (GTR) in 27 (64.3%), subtotal (STR) in 15 patients (35.7%). Morphologically 45.2% were grade 2 and 54.8% were grade 3. Molecular grouping was split as PFA in 73.8% and PFB in 26.2%. Postoperative RT was given locally in 26, and with craniospinal fields in 3 patients. Thirteen patients did not receive adjuvant RT. Median total dose was 54 Gy (range, 37.8 -73.8 Gy). Adjuvant CT was given in 76.2%. Median follow-up was 69 months (range, 13-286 m). For the whole cohort local control (LC) at 5 years was estimated as 52.7%, spinal disease control 90%, progression free survival (PFS) 50.5% and overall survival (OS) 70.6%. LC at 5 years was 42.9% for PFA and 81.8 for PFB (p = 0.135); OS 65.8% for PFA and 85.7% for PFB (p = 0.374). LC was 66.7% in GTR and 20.6% in STR (p = 0.024); OS 80.2% in GTR and 49.9 in STR (p = 0.03). In >3y cohort where all patients received adjuvant RT, LC was 63.2%; while in <3y cohort (adjuvant RT in 43.4%) LC was 43.5% (p = 0.055). Although PFB group PFEs appear to have a better prognosis compared to PFB group, extent of surgical resection is still the most important prognostic factor for LC and OS. In patients <3y, despite its potential long-term side effects RT needs to be implemented early in the treatment for better LC. In PFB patients with good prognosis role of RT needs to be investigated in prospective studies.

Q: Can you tell us about the ongoing “Elderly Glioblastoma” trial? What is the rationale and background for this trial?

Abstract BACKGROUND Although the word “glioblastoma” still denotes a grade-IV pathology, basic molecular studies have clearly indicated that a significant proportion of lower-grade gliomas harbor genetic alterations typical of glioblastomas. Based on these findings cIMPACT-NOW update 3 has defined an entity called the “diffuse astrocytic glioma, IDH-wildtype, with molecular features of glioblastoma, WHO grade IV”. A TERT-promoter mutation is one of these typical molecular markers of glioblastomas. In this study we analyzed IDH-wild type, TERT-mutant diffuse gliomas of different pathological grades to look for differences in demographic, clinical and survival characteristics. MATERIAL AND METHODS 147 adult hemispheric diffuse-gliomas with wild-type IDH1/2 and mutant TERT-promoter (C228T or C250T) were retrospectively analyzed. Primary thalamic, cerebellar brainstem or spinal cases were excluded. 126 (86%), 16(11%) and 5(3%) patients were WHO grade IV, III and II respectively. After surgical treatment or stereotactic biopsy all patients underwent chemoradiation. Median follow-up was 16mo (1–110). Tumors of different grades were compared for age, gender, multifocality, gliomatosis pattern, Ki-67 index, progression-free survival and overall-survival. RESULTS Mean age at presentation for grade II, III and IV were comparable (58.1, 58 and 58.1; ANOVA, p=0.72). There was a slight male predominance in both lower-grades and WHO-grade IV (M:F ratios 1.625 and 1.74). Mean Ki-67 index was significantly higher in higher grades (0.06, 0.14 and 0.25 for grades II, III and IV; ANOVA, p=0.001). Multifocality was comparable (chi-sq, p=1) in lower-grades (3/21; 14.3%) vs. WHO-grade IV (18/126; 14.3%). Gliomatosis pattern was comparable (chi-sq, p=0.095) in lower-grades (2/21; 9.5%) vs. (3/126; 2.3%). Median recurrence free survival (RFS) was 16 months (0–63) in lower-grades and 8months (1–50) in WHO-grade IV. PFS was significantly different between 3 WHO-grades (Log rank, p=0.007) and also between lower-grades and WHO-grade IV (Log rank, p=0.002). Median overall survival was 26 months(2–110) in lower-grades and 15mo(1–91) in WHO-grade IV. OS was significantly different between 3 WHO-grades (Log rank, p=0.014) and also between lower-grades and WHO-grade IV (Log rank, p=0.007). CONCLUSION Increasing pathological grades of hemispheric “IDH-wild type, TERT-mutant diffuse gliomas” have similar demographic and clinical characteristics but incrasing proliferation indices, decrasing progression free survival and shorter overall survival. The findings may be suggesitve of different grades of one common tumor entity.

Magnetic resonance (MR) image-guided radiotherapy (MRIgRT) has been recently implemented in routine clinical practice in our department. Treatment workflow for MRIgRT differs substantially from other radiotherapy systems and consists of set-up, MR imaging, re-contouring, re-optimization & plan QA and treatment delivery. We hypothesized that delivery of total on table treatment time will be less than 60 minutes for >75% of fractions. Aforementioned treatment components were recorded in 44 patients (304 fractions), treated between September 2018 and January 2019 with our linear accelerator based MRIgRT. Effect of treatment parameters (treatment site, dose per fraction, being first or last fraction, being treated with adapted plan or not, using breath hold technique or not) on total treatment time were analyzed. Median age was 66 years (28-83). Upper abdomen (21 patients, 41.1%) and pelvic (17 patients, 33.3%) regions were most common sites treated. Most common diagnosis was prostate cancer (14 patients - 31.8%). Majority of patients (40 patients, 91%) were treated with stereotactic body radiotherapy (SBRT), with fraction number 8 or less. Twenty-nine patients (56.8 %) were treated with audio-visually coached breath-hold gating method. Median total dose was 36.25 Gy (24 – 70 Gy) and median fraction number is 5 (3 – 28). Median total treatment time for all fractions was 43.5 minutes (range, 21-125 ) with 85% of patients being treated in less than 1 hour. Median patient setup time was 10 minutes (range 5-31), contouring time was 8 minutes (range 1-45), re-optimization + QA time was 4,5 minutes (range 1-16). Median time lost due to technical problems was 7 minutes (range 2-49) and occurred in 86 fractions. The longest component of the workflow was found to be radiotherapy treatment delivery; median 18 minutes (range 8-76). There was correlation with the treatment site and the total treatment time (p<0.0001) Median total treatment durations for upper abdomen, pelvis, thorax and spine were 48.3, 40.9, 42.2 and 53 minutes, respectively. As expected, lower fraction doses (< vs > 6 Gy) resulted in shorter treatment time (median 39.4 vs 47.2, p<0.0001). Breath hold technique resulted in longer overall treatment time compared to non-breath hold techniques (median 41.7 vs. 45.1, p=0.01). Similar difference was noticed in total treatment time between fractions treated with the original plan or the adapted plan (median 38.9 vs. 45.3, p<0,0001). There was a gradual decrease in treatment time between the first and last fraction (median 51 vs 41.7, p<0.0001). Total treatment time was found to be longer for SBRT compared with non-SBRT fractions (median 45 vs 40.5, p=0.001). MRIgRT can be easily delivered in less than 1 hour in 85% of fractions if appropriate precautions are taken. Radiotherapy delivery time remains the longest component of overall treatment. Optimization of the workflow and future hardware changes are expected to further reduce overall delivery times.