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Soo Park, MD
Soo Park, MD
Posted: Wednesday, July 3, 2024
When PD-1–targeted immune checkpoint inhibitor therapy is given to patients with advanced cutaneous squamous cell carcinoma, the rates of complete metabolic response and partial metabolic response are high. However, when postinitiation fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT imaging is done early—fewer than 4 months after immune checkpoint inhibitor therapy—and results show a patient is not responding to it, this information may help guide treatment decisions going forward, according to Rahul Ladwa, MD, of the University of Queensland, Brisbane, Australia, and colleagues. The team presented the results of their single-center retrospective study during the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 9548).
“Early PET complete metabolic response/partial metabolic response appears to predict long-term durable responses,” noted the investigators.
The investigators focused on a cohort of 53 patients treated with immune checkpoint inhibitors for advanced squamous cell skin cancer between 2018 and 2023 who had serial 18F-FDG PET/CT with 4 or fewer months between treatment and second PET.
At the second PET, the responses of the cohort were complete metabolic response, 54.7%; partial metabolic response, 15.1%; stable metabolic disease, 11.3%; and progressive metabolic disease, 18.9%. At data cutoff, 94.6% of the patients with a 4-month assessment of complete or partial metabolic response had experienced clinical disease progression; further, 94.7% of those who responded clinically at 4 months maintained their response for a minimum of 12 months. However, at a median follow-up of 8 months, progressive disease was observed in 11 of the original 53 patients (21%). In the entire cohort, median time to disease progression was significantly higher in those patients with a complete or partial metabolic response vs those with stable metabolic disease or progressive metabolic disease: 55 vs 4 months, P < .001.
Disclosure: For full disclosure of the study authors, visit coi.asco.org.
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