Using an artificial intelligence tool to improve the recognition of pseudoprogression in pleural mesothelioma patients treated with immunotherapy: a case series

Background: Pseudoprogression, defined as initial radiological tumor growth followed by treatment response, can complicate treatment response assessment in patients receiving immunotherapy. In pleural mesothelioma (PM) patients treated with immunotherapy reliable identification of pseudoprogression remains challenging with the modified Response Evaluation Criteria in Solid Tumors (mRECIST) v1.1 criteria. Automated volumetric assessment using an artificial intelligence (AI) tool (ARTIMES) may provide additional insight into tumor response patterns. We aim to describe cases of pseudoprogression identified using the ARTIMES criteria in PM patients treated with immunotherapy.

Case Description: We performed a retrospective observational study of adult PM patients treated with immunotherapy at a tertiary center between January 1, 2013 and July 1, 2022. Tumor volumes were automatically segmented and quantified using the ARTIMES model. Patients demonstrating disease progression according to ARTIMES criteria followed by subsequent tumor volume decrease were evaluated for pseudoprogression. The results were presented in graphs depicting tumor volume, treatment duration, and the start and stop dates of immunotherapy. Among 368 PM patients treated with immunotherapy, 8 patients met inclusion criteria for confirmed pseudoprogression. All patients were male, with a median age of 67.5 years. Most patients had epithelioid histology (75.0%). All patients showed initial volumetric progression on early follow-up imaging, followed by objective tumor volume reduction either during continued immunotherapy or after treatment discontinuation. Volumetric tumor tracking enabled visualization of delayed responses that would have been difficult to interpret using standard imaging comparisons alone.

Conclusions: Pseudoprogression occurs in a subset of PM patients treated with immunotherapy. Automated volumetric tumor assessment can help identify pseudoprogression patterns. Integrating volumetric analysis with clinical evaluation may reduce premature discontinuation of potentially effective immunotherapy.