ESTRO 37 Abstract book

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ESTRO 37

22.8% radiotherapy, and 43.8% systemic therapy. 17.7% (n=133) were participating in a clinical trial. Reasons for participation were: personal contribution to cancer research (72.2%), trial treatment is more intensive (33.8%) or more innovative (25.6%), treatment by disease specialists (21.1%), newest treatment method (15.0%), or previous positive experience with clinical trials (6.0%). Out of the patients not participating in a trial, 94 (15.2%) were offered to participate and refused due to extensive travel time to the center (21.3%), no therapeutic advantage (20.2%), too time-consuming (17.0%), too many additional appointments (7.5%), higher risk (10.6%), participating in another trial (4.3%), insufficient information by the physician or bad experience in the past (both 3.2%). Out of the patients not offered to participate in a trial (n=504), 50.2% would participate due to: personal contribution to cancer research (66.4%), trial treatment is more intensive (49.8%) or more innovative (53.4%), treatment by disease specialists (39.9%), newest treatment method (41.1%), or previous positive experience with clinical trials (7.5%). Of all, 23.6% informed themselves about clinical trials via internet (64.5%), family physician/specialist (59.0%), or in a medical magazine (10.2%). Only 8.3% used the clinic homepage as a source of information, of those 83.1% were satisfied with its content. We further asked how patients want to be informed about possible clinical trials for their disease. Most (42.7%) preferred an individual medical consultation with their physician, 16.9% would prefer information flyers/brochures, 14.2% special patient events, 13.9% information on the clinic homepage, and 3.3% through a clinic app. Conclusion Clearly, patients are willing to participate in clinical trials. Better information strategies need to be implemented and physicians need to be aware of running trials within their department and improve recruitment by counseling patients effectively. Trial concepts should keep in mind patients’ needs including adequate number of appointments, positive risk-benefit profiles and information material. OC0095 Use of a patient reported outcome as a potential radiobiological endpoint in oropharyngeal cancer M. Hickman 1 , S. Kelly 1 , C. Fong 2 , P. Nightingale 1 , P. Sanghera 2 , H. Mehanna 3 , A. Hartley 2 1 University Hospital Birmingham, Radiotherapy, Birmingham, United Kingdom 2 Queen Elizabeth Hospital Birmingham, Hall-Edwards Radiotherapy Research Group, Birmingham, United Kingdom 3 University of Birmingham, InHanse, Birmingham, United Kingdom Purpose or Objective Historically mucositis has been scored using clinician scoring of mucosal appearances (e.g. Common Terminology Criteria for Adverse Events (CTCAE) version (v) 3) or patient symptoms (CTCAEv4). More recently the patient reported outcome version of CTCAE (PRO-CTCAE) has been developed. The purpose of this study was to investigate the relationship between radiobiological parameters and the duration of mucosal outcomes measured using CTCAE v3, v4 and PRO-CTCAE. Material and Methods The mucosal reactions of consecutive patients undergoing radical intensity modulated radiotherapy were scored weekly by clinicians and patients. Reactions continued to be scored during post treatment visits until grade 3 reaction had subsided (v3 and v4) or patients reported that the severity of their throat or mouth sores in the last week had decreased from severe to moderate (PRO). The relationship between the volume of high dose CTV, prescription dose converted to biologically effective

dose with mucosal parameters (BED) (α/β=10 Gy, α=0.3 Gy -1 , T k =7 days, T p =2.5 days) and BED modified to take in to account the effect of synchronous chemotherapy (mcBED) (T p =5 days) and the duration of grade 3 reactions (v3 and v4) and severe throat or mouth sores (PRO) was investigated using spearman’s rho correlation coefficients. Results The study is ongoing but 44 patients have completed the post treatment phase. Prescription doses were 70Gy/35# (n=6), 65 Gy/30# (n=35), 64Gy/25# (n=2) and 55Gy/20# (n=1). Synchronous chemotherapy was cisplatin (n=35), carboplatin (n=3), cetuximab (n=1), radiotherapy alone (n=5). Mean high dose CTV volume was 200cm 3 (range 29- 533cm 3 ). Median duration of grade 3 reactions was 7 weeks (wks) (0-14 wks) (v3), 8 wks (0-15wks) (v4). Median duration of severe mouth or throat sores was 7.5 wks (0- 15 wks) (PRO). There was no significant correlation between high dose CTV volume, BED, and mcBED with duration of grade 3 mucositis as measured using CTC v3 or v4. However, there was a significant correlation between both high dose CTV volume (p=0.006) and mcBED (p=0.044) with duration of mouth and throat sores (PRO). Conclusion Early results from this ongoing study suggest that the duration of patient reported severe mouth or throat sores correlates with the volume of the high dose CTV and the prescription dose when this is converted into BED using mucosal parameters corrected for synchronous chemotherapy. Given that this relationship was not seen with v3 and v4 it is possible that this patient reported outcome may be more sensitive to changes in mcBED and CTV volume and has a potential as an endpoint in both volumetric and dosimetric escalation/de-escalation studies. OC-0096 Late toxicity of prostate stereotactic ablative radiotherapy treated with flattening filter free A. Duffton 1 , L. Devlin 1 , A. Sadozye 2 , P. McLoone 3 , N. MacLeod 2 , C. Lamb 2 , S. Currie 4 , D. Dodds 2 1 Beatson West of Scotland Cancer Centre, Radiotherapy, Glasgow, United Kingdom 2 Beatson West of Scotland Cancer Centre, Clinical Oncology, Glasgow, United Kingdom 3 University of Glasgow, Institute of Health & Wellbeing, Glasgow, United Kingdom 4 Beatson West of Scotland Cancer Centre, Clinical Physics and Bioengineering, Glasgow, United Kingdom Purpose or Objective Stereotactic ablative radiotherapy (SABR) for prostate cancer allows high doses of radiotherapy to be delivered with high precision over a short course of treatment. Here, we report the clinical outcomes at 12 month follow-up in a prospective safety and feasibility study where patients were treated with Rapidarc® and flattening filter free (FFF). Material and Methods Male patients with low-intermediate risk prostate cancer were enrolled in this prospective, ethically approved study. Initial PSA (iPSA) of ≤20ng/ml, Gleason score 6-7. Patients had MR/CT fusion for delineation of prostate +/- seminal vesicles. CT/MR fusion images were used for delineation of the target volume and planned using Rapidarc® FFF. Patients received 35Gy in 5 fractions. On treatment CBCT imaging with fiducial markers were used for set-up correction. For late toxicity (≥ 90 days after radiotherapy) GU and GI symptoms were assessed and recorded 6 monthly following treatment using RTOG scoring criteria. Results Forty-one patient treated for low-intermediate risk prostate cancer were recruited to the study. 24 (58.5%)