Quantitative Analysis of PET/CT Images of Immune Related Side Effects in Metastatic Melanoma Patients

New cancer treatment with immune-checkpoint inhibitors (ICIs) has changed the way patients with melanoma and a variety of other cancers are being treated. Many pivotal trials that showed efficacy and safety of ICIs were performed in malignant melanoma. ICI can cause a different type of toxicity, called immune-related adverse events (irAEs). Though the exact pathophysiology is not completely understood, it is believed that irAEs are provoked by immune upregulation and inflammation. However, they can be serious, life-threatening, and warrant hospital admission as well. Dangerous irAEs include myocarditis, myositis, and pneumonitis, among others. Due to the novel mechanism of action, unpredictable nature, and wide usage of this type of treatment in the future, there is urgent need for better control of these potentially dangerous side effects. Early recognition and treatment of irAEs are of great importance in successful management. Positron emission tomography-computed tomography (PET/CT) with \[18F\]2fluoro-2-deoxy-D-glucose (18F-FDG) is a sensitive, non-invasive, and widely used method for diagnosis and evaluation of treatment efficacy of malignant melanoma. The combination of 18F-FDG-PET and CT allows for assessment of both functional and morphological status of the lesions, and so facilitates better clinical decisions and patient care during treatment. It is also a very sensitive method for recognising inflammation, that can be a signal of irAEs. Quantitative analysis is a rapidly evolving field of PET/CT image analysis. It includes both radiomics and artificial intelligence. Some studies have reported that quantitative analysis could predict efficacy of different cancer treatments. Quantitative image analysis in cancer response assessment is a rapidly expanding field, with the ultimate goal of clinical translation. However, in the specific instance of irAE diagnosis, it is not yet clear what role quantitative analysis of PET/CT scans can play. The hypothesis i