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Vienna, Austria

ESTRO 2023

Session Item

Saturday
May 13
10:30 - 11:30
Plenary Hall
Upper GI
Marianne Nordsmark, Denmark;
Martijn Intven, The Netherlands
Proffered Papers
Clinical
11:10 - 11:20
SCOPE2 PET: continuing CisCap v switch to CarPac in PET non-responders on dCRT for esophageal cancer
Somnath Mukherjee, United Kingdom
OC-0103

Abstract

SCOPE2 PET: continuing CisCap v switch to CarPac in PET non-responders on dCRT for esophageal cancer
Authors:

Somnath Mukherjee1, Chris Hurt2, Sarah Gwynne3, Lisette Nixon2, Sarah Bridges2, Richard Adams2, Ganesh Radhakrishna4, Tim Maughan5, Marie-Clare Hunter2, Rashmi Kumar2, Rajarshi Roy6, Christopher Jones7, Christopher Marshall8, Kevin Bradley8, Debbie Callaghan6, Simon Gollins9, Hamid Sheikh4, Andrew Bateman10, Stephen Falk11, Bethan Tranter12, Geraint John Lewis13, Emiliano Spezi14, Maria Hawkins15, Tom Crosby16

1Oxford University Hospital NHS Foundation Trust, Oncology, Oxford, United Kingdom; 2Cardiff University, Centre For Trials Research, Cardiff, United Kingdom; 3Swansea Bay University Health Board, Oncology, Swansea, United Kingdom; 4The Christie NHS Foundation Trust, Oncology, Manchester, United Kingdom; 5University of Oxford, Oncology, Oxford, United Kingdom; 6Hull University Teaching Hospitals NHS Trust, Oncology, Hull, United Kingdom; 7University of Cambridge, Oncology, Cambridge, United Kingdom; 8Cardiff University, Wales Research and Diagnostic PET Imaging Centre, Cardiff, United Kingdom; 9Betsi Cadwaladr University Health Board, Oncology, Rhyl, United Kingdom; 10University Hospital Southampton NHS Foundation Trust, Oncology, Southampton, United Kingdom; 11University Hospitals Bristol NHS Foundation Trust, Oncology, Bristol, United Kingdom; 12Velindre University NHS Trust, Pharmacy, Cardiff, United Kingdom; 13Velindre University NHS Trust, Medical Physics, Cardiff, United Kingdom; 14Cardiff University, School of Engineering, Cardiff, United Kingdom; 15University College London, Oncology, London, United Kingdom; 16Velindre University NHS Trust, Oncology, Cardiff, United Kingdom

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Purpose or Objective

The randomised phase II/III SCOPE2 is investigating two questions in patients with oesophageal squamous carcinoma (SCC) and adenocarcinoma (ACA) receiving definitive chemoradiation (dCRT): 1) does high dose RT (60Gy/25#) improve OS compared to standard dose (50Gy/25#) and 2) In PET non-responders (based on FDG-PET-CT on day 14 of cycle 1 induction chemotherapy) does switching chemotherapy from Cisplatin-Capecitabine (CisCap) to Carboplatin-Paclitaxel (CarPac) after 1 cycle improve treatment failure-free survival (TFFS) at 24 weeks. The dose escalation component (randomised phase III) is still ongoing; here, we report results of the PET substudy

Material and Methods

Design: The PET substudy is a randomised Phase II component of a multicentre, open label, parallel, 2x2 (four arm) factorial study.

Key Eligibility: Histologically confirmed cancer oesophagus/GOJ with <2cm extension into the stomach; selected for dCRT by a designated Multidisciplinary Team Meeting; age>=18; WHO PS 0-1; T1-4 and N+/-; total disease length ≤13cm. Baseline FDG-PET SUVmax ≥ 5 (performed within 5 weeks prior to start of treatment).

Procedures: Repeat PET performed on Day 14 of 1st cycle of induction CisCap. Non-responders (drop in SUVmax<35%) were randomized to continue CisCap or switch to CarPac for cycle 2 followed by concurrent CRT with same chemotherapy. All patients were also randomized between 50Gy and 60Gy arms.

Statistical Consideration: PET substudy was powered separately in SCC and ACA. For SCC 86 non-responders were required to detect a 20% improvement in 24wk TFFS (55% to 75% with CarPac; chi square, 87% power, 0.2 one sided alpha). For ACA, 27 patients would detect an improvement in 24 week TFFS from 55% with to 85% with CarPac (chi square, 80% power, 0.20 one sided alpha).

RT Quality Assurance: An associated RTQA program ensured high quality RT was delivered.

Funding: Cancer Research UK (A17606) and

Trial Sponsor: Velindre University NHS Trust.


















Results

IDMC stopped PET substudy in Aug 2021 on the grounds of futility and possible harm. 63/103 (61%) participants were non-responders (SCC=52/83; ACA=11/20) of whom 32 were randomised to continue CisCap and 31 switched to CarPac. The 24 week TFFS in the SCC cohort was no better in responders (who continued CisCap) than non-responders who stayed on CisCap or switched to CarPac (78.6% v 92.6% v 68%). In non-responders (SCC cohort) both 24-week TFFS [25/27(92.6%) vs 17/25(68%) p=0.028] and OS (42.5 mo v 20.4mo, adjusted HR 0.36, p=0.018) favoured CisCap over CarPac. PFS favoured CisCap but was non-significant (34.6 mo v 19.4mo, HR 0.58, p=0.15). Similar trend was seen in ACA (p=NS). Grade 3 /4 toxicity rate was comparable between arms [CarPac 22/31 (71.0%) vs CisCap 21/31 (67.7%)].

Conclusion

Early PET response based on proposed SUVmax cut-off was not prognostic and did not predict treatment failure. Chemo-switch based on early PET response using proposed cut-off cannot be recommended in this setting. A better discriminator for early treatment failure is required.