Patient survival prediction based on PET/CT radiomics extracted from metastatic melanoma bone lesions

This study aimed to evaluate the prognostic value of FDG-PET/CT-based radiomic signatures of bone lesions for predicting overall survival (OS) in metastatic melanoma patients treated with immune checkpoint inhibition (ICI).

Thirty-six consecutive metastatic melanoma patients treated with ICI at the University Hospital Zurich were included in this study. All patients had at least one bone metastasis at baseline, and PET/CT imaging data were available. The clinical endpoint was defined as patient OS. Radiomic features were extracted from each lesion and were correlated with patient OS. For patients with multiple bone lesions, radiomic data were pooled using three methods: arithmetic mean, mean weighted by lesion volume and selection of the largest lesion. Multivariate models were internally validated with nested cross-validation, and the area under the receiver operating characteristic curve was used as the performance metric.

The median OS was 5.1 years. Among the models predicting 3-year OS post-treatment, the highest performance was demonstrated by the combined PET/CT model integrating features from all aggregation methods, achieving an AUC of 0.76 (95% CI: 0.57-0.95). For 5-year OS prediction, the best performance was also observed for the combined PET/CT model, with an AUC of 0.84 (95% CI: 0.71-0.98), using radiomic features extracted from the largest lesions.

FDG-PET/CT-based radiomic signatures of bone lesions in metastatic melanoma patients show potential for predicting overall survival. These findings suggest that radiomics could serve as a tool for guiding treatment decisions in patients with bone metastases undergoing immune checkpoint inhibition.