Fig. 2.

Comparison of RECIST 1.1 and iRECIST criteria for evaluation of a 45-year-old woman with metastatic melanoma treated with ipilimumab (antiCTLA-4) and nivolumab (anti-PD-1). Baseline CT image (November 2017) shows a 13-mm lung metastasis (target lesion, upper panel, arrow) and a 10-mm short-axis axillary lymph node (non-target lesion, lower panel, arrow). On a 3-month follow-up, both lesions enlarged with an increase of 38% of the target lesion leading to a progressive disease (PD) and a stop of treatment according to RECIST 1.1 and an unconfirmed PD with maintained treatment according to iRECIST criteria. On the two following CT examinations (March and June 2018), the lung metastasis decreased in size, but the axillary lymph node was stable (unconfirmed PD) but still significantly enlarged compared to the baseline (still unconfirmed PD according to iRECIST criteria). Finally, on August 2018, CT images showed a decrease in size of both lesions, confirming the pseudoprogression with a response assessed to be -70%, leading to a partial response according to iRECIST criteria