ESTRO 2022 - Abstract Book

S77

Abstract book

ESTRO 2022

At median follow-up of 2.0 years (IQR 0.0-3.1) the 3-year rates of ipsilateral arm lymphedema were 11.7% in the whole group, whilst in the 50 Gy versus 40 Gy group it was 11.6% versus 11.8%, absolute difference 0.1% (95% CI -0.4% to 0.4%), p=0.96. Range of shoulder motion was not impaired (<20% different) in 97.5%, the frequencies being 96.3% (50Gy) versus 98.7% (40Gy), no difference. Breast induration in post-lumpectomy patients was 26.0% (22.9% (50Gy) vs 29.1% (40Gy), p=0.11. In patients treated with/without SIB, induration was 22.0% versus 29.5%, difference 7.4% (p=0.12). Overall, the 3-year risk of loco-regional recurrence was 1.8% (1.2-2.7) (50Gy) and 1.8% (1.1-2.7) (40Gy), risk of distant failure was 5.6% (4.3-7.1) (50Gy) and 6.9% (5.5-8.6) (40Gy), and risk of death was 3.7% (2.6-5.0) (50Gy) and 4.8% (3.6-6.2) (40Gy).

Conclusion Moderately hypofractionated loco-regional breast cancer irradiation of node-positive breast cancer does not result in more arm lymphedema compared to standard fractionated therapy. The 3-year loco-regional recurrence risk was very low. Moderately hypofractionated RT did not influence the risk of distant recurrence or death.

Funding: The Danish Cancer Society and DCCC RT (Danish Comprehensive Cancer Centre RadioTherapy Group)

OC-0103 SCALOP2:A multicenter randomized trial of RT dose escalation and nelfinavir in pancreatic cancer

S. Mukherjee 1 , C. Qi 2 , R. Shaw 3 , J. Bridgewater 4 , G. Radhakrishna 5 , N. Patel 6 , B. Tranter 7 , P. Parsons 8 , S. Falk 9 , H. Wasan 10 , D. Holyoake 11 , R. Roy 12 , M. Scott-Brown 13 , C. Hurt 14 , D. Sebag-Montefiore 15 , T. Maughan 16 , M. Hawkins 17 , P. Corrie 18 1 Oxford University Hospital NHS Trust, Oncology, Oxford, United Kingdom; 2 Centre for Statistics in Medicine, University of Oxford, Statistics, Oxford, United Kingdom; 3 University of Oxford, Oxford Clinical Trials Unit, Oxford, United Kingdom; 4 University College London Cancer Institute, Oncology, London, United Kingdom; 5 The Christie NHS Foundation Trust, Oncology, Manchester, United Kingdom; 6 Oxford University Hospitals NHS Foundation Trust, Radiology, Oxford, United Kingdom; 7 Velindre Hospital NHS Foundation Trust, Pharmacy, Cardiff, United Kingdom; 8 Velindre Hospital NHS Foundation Trust, Radiotherapy Physics, Cardiff, United Kingdom; 9 Bristol Oncology Centre, Oncology, Bristol, United Kingdom; 10 Hammersmith Hospital, Imperial College London, Division of Cancer, London, United Kingdom; 11 Norfolk and Norwich University Hospitals NHS Foundation Trust, Oncology, Norwich, United Kingdom; 12 Hull University Teaching Hospitals NHS Trust, Oncology, Hull, United Kingdom; 13 University Hospital Coventry and Warwickshire, Oncology, Coventry, United Kingdom; 14 Cardiff University, Centre for Trials Research, Cardiff, United Kingdom; 15 St. James's University Hospital, Institute of Oncology, , Leeds, United Kingdom; 16 MRC Oxford Institute for Radiation Oncology, University of Oxford, Oncology, Oxford, United Kingdom; 17 University College London, Dept of Med Phys & Biomedical Eng, London, United Kingdom; 18 Cambridge University Hospitals NHS Foundation Trust, Oncology, Cambridge, United Kingdom Purpose or Objective The anti-retroviral agent, nelfinavir (N), demonstrated radiosensitising properties in pre-clinical models and showed promising activity in single arm phase I/II trials in combination with CRT for LAPC. RT dose escalation (BED10 >70) may be associated with improved survival. SCALOP2 was a phase 1/randomized phase II study. The phase I component established the MTD of nelfinavir in combination with capecitabine-based CRT following gemcitabine+nab-paclitaxel (GEMABX) induction chemotherapy in LAPC (previously reported). The 2 x 2 randomized phase II component evaluated whether (1) RT dose escalation from 50.4Gy/28 fractions [standard dose (SD)] to 60Gy/30 fractions [high dose (HD)], combined with capecitabine improved OS and (2) adding nelfinavir to CRT improved PFS. Materials and Methods Patients with unresectable, histologically/cytologically proven LAPC and WHO PS 0-1 received 3 cycles of induction GEMABX (standard dose and schedule) followed by restaging. Progression-free patients were randomized to 1 further cycle of GEMABX followed by A (SD+N), B (SD = control arm), C (HD +N), D (HD), or E (GEMABX x 2 cycles = calibration arm). CRT capecitabine dose was 830mg/m2 bd on days of RT, nelfinavir 1250mg bd started 7 days before CRT until completing CRT. Results Between March 2016 and March 2020, 186 patients were recruited from 21 centres in the UK (phase 1=27; phase 2=159). 106/159 patients were randomized (A=19, B=26, C=19, D=27, E=15). Arm E closed in Nov 2019, taking into consideration data from the LAPACT trial. The ISDMC recommended closure of the nelfinavir arms in Feb 2020 due to futility. At the time of analysis, 64/91 patients randomized to CRT arms had died. Median OS was 15.6 mo (60% CI 14.3,18.2) in the SD arms and 16.9 mo (16.2, 17.7) in the HD arms, HR (60% CI) 1.11(0.89,1.38), adjusted one-sided p=Not significant (NS). Of the 76 patients eligible for randomization to N-containing arms, median PFS was 11.1 (10.3, 12.8) in the CRT-only arms (HR (60% CI) 1.84(1.47,2.3) and 10 mo (60% CI 9.9,10.2) in the CRT+N arms, adjusted one-sided p=NS. Secondary endpoints: Grade