Angela Aldin1, Marialena Trivella2, Lise J. Estcourt3, Gary Collins4, Karel Moons5, Andreas Engert6, Bastian von Tresckow6, Carsten Kobe7, Farid Foroutan8, Nina Kreuzberger1, Nicole Skoetz9
1 Cochrane Haematological Malignancies Group, Department I of Internal Medicine, University Hospital of Cologne, Cologne, Germany, 2 Centre for Statistics in Medicine, University of Oxford, Oxford, UK, 3 Haematology/Transfusion Medicine, NHS Blood and Transplant, Oxford, UK, 4 Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK, 5 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, Netherlands, 6 Department I of Internal Medicine, University Hospital of Cologne, Cologne, Germany, 7 Department for Nuclear Medicine, University Hospital of Cologne, Cologne, Germany, 8 Cardiology, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada, 9 Cochrane Cancer, Department I of Internal Medicine, University Hospital of Cologne, Cologne, Germany
Background: Interim FDG-PET has been suggested as a prognostic factor as it can identify the state of the disease during chemotherapy, and thereby distinguish between patients with a poor prognosis (interim-PET positive) from those with a better prognosis (interim-PET negative). This distinction allows for treatment adaptation to achieve the best possible treatment outcome for each group.
Aim: To meta-analyse results on the association between interim-PET scan results and overall survival (OS), progression-free survival (PFS) and adverse events (AE).
Methods: Based on a-priori Cochrane protocol, we developed sensitive search strategies for CENTRAL, MEDLINE, databases of ongoing trials and conference proceedings (search date 07/2017). Two authors independently assessed studies for eligibility using pre-defined inclusion and exclusion criteria, and then extracted data and assessed the methodological quality. We used hazard ratios (HR) as an effect measure. In case HR were not reported, we estimated it where possible using other available data, or contacted the authors to request additional data. We included studies which evaluated interim-PET as a prognostic factor after a few cycles of first-line chemotherapy in adult patients with HL. We excluded studies which modified treatment based on interim-PET results in order to draw an unbiased conclusion on the prognostic ability of interim-PET.
Results: We identified 23 studies, including 6046 patients. For OS, we pooled data from eight studies where interim-PET was conducted after two cycles of ABVD. The meta-analysis shows greater OS for patients with a negative interim-PET scan compared to patients with a positive scan (HR 8.95, 95% CI 4.60, 17.39). We identified 21 studies that fully or partially report data for PFS. No study reports AE.
Conclusion: Interim-PET can be considered a prognostic factor for OS in univariate analysis. For PFS, to be able to evaluate comparability of the studies and to take a decision on inclusion for meta-analysis, we have contacted authors for additional information. The lack of standard reporting of prognostic studies, and the consequential poor quality and reliability of reported data, makes it difficult to give final conclusions at this stage.
This project was funded by the German Federal Ministry of Education and Research, grant number 01KG1709.