Cancer Imaging (Oct 2021)

FDG-PET/CT imaging for evaluating durable responses to immune check point inhibitors in patients with advanced cutaneous squamous cell carcinoma

  • Luke S. McLean,
  • Karda Cavanagh,
  • Rodney J. Hicks,
  • Jason Callahan,
  • Jing Xie,
  • Anthony Cardin,
  • Annette M. Lim,
  • Danny Rischin

DOI
https://doi.org/10.1186/s40644-021-00426-2
Journal volume & issue
Vol. 21, no. 1
pp. 1 – 6

Abstract

Read online

Abstract Background The role of FDG-PET/CT imaging in assessing response to immunotherapy in advanced cutaneous squamous cell carcinoma (CSCC) is unknown. This study compared complete metabolic response (CMR) rates by FDG-PET and RECIST1.1 via CT or MRI in patients on cemiplimab for > 10 months. Methods This was a single-centre retrospective study of 15 patients treated with cemiplimab for advanced CSCC who had CT/MRI and FDG-PET/CT at > 10 months to assess metabolic treatment response. The median age was 73 years (range 55–84) and 93% were male. RECIST1.1 and PERCIST1.0 tumor responses were evaluated by blinded readers. Results Seventy-three percent (11/15) (95%CI 44.9, 92.2%) achieved a CMR on PET. Of these 11, on RECIST1.1 there was one complete response, 9 partial responses and one stable disease. Conclusions In patients on cemiplimab for > 10 months, there was discordance between CR rates on FDG-PET versus RECIST1.1. FDG-PET/CT may have utility for clarifying depth of response in patients treated with immunotherapy for CSCC.

Keywords