Immunotherapy (IT) is now a standard of care in advanced NSCLC patients. However, patients may present with various patterns of response, including initial progression followed by long stabilization or response, making it difficult to decide whether or not we should continue the treatment at the occurrence of progression. Our aim was to explore the patterns of responses based on CT-scans in order to differentiate real progression (PD) from pseudoprogression (PsPD).
We conducted a retrospective analysis of all NSCLC patients treated with IT in our Institution. All CT-scans were reviewed and the responses were assessed by RECIST 1.1 and iRECIST criteria. Seven different patterns of PD were considered based on the combination of target (T) and/or non-target (NT) and/or new lesions (NL). A confirmatory CT scan was performed at 4 weeks to discriminate real progression from PsPD. PsPD was defined as any decrease or stable disease for at least 6 months following an initial progression. Dissociated responses (DR) were defined as concomitant progressing and responding lesions for patients treated at least 6 months. Patterns of PD were correlated with overall survival (OS).
Out of 202 patients treated by IT, 39 patients (19%) were excluded due to the absence of confirmatory CT. 87 patients (53%) had an initial PD, confirmed by a subsequent CT, or by death related to tumor progression. 14 patients (9%) experienced PsPD or DR. PsPD or DR patients had higher OS than PD patients (p =
On the first occurrence of progression upon IT, a concomitant increase of T, NT and appearance of NL or appearance of extra-thoracic visceral lesions were strongly suggestive of real PD. IT should be stopped in these patients, and a confirmatory CT scan should be avoided.
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A. Marabelle: Reports personal fees from Roche/Genentech, personal fees from Bristol-Myers Squibb, personal fees from Merck, personal fees from Pfizer, personal fees from AstraZeneca, outside the submitted work. D. Planchard: Reports consultancy for Boehringer Ingelheim, Lilly, MSD, Novartis, Chagai, Roche/Genentech, Bristol-Myers Squibb, Merck, Pfizer, AstraZeneca, outside the submitted work. J-C. Soria: Discloses consultanty fees from AstraZeneca, Astex, Clovis, GSK, Gammamabs, Lilly, MSD, Mission Therapeutics, Meurs, Pfizer, PharmaMar, Pierre Fabre, Roche, Sanofi, Servier, Symphogen, Takeda B. Besse: Discloses research grants from Bristol-Myers Squibb, MSD, Roche, Merck and AstraZeneca All other authors have declared no conflicts of interest.