[Overview of immune checkpoint inhibitor therapy : What the radiologist should know]

In recent decades, oncology has been fundamentally transformed by immune checkpoint inhibitors (ICIs). By blocking inhibitory molecules that normally inhibit T cell activation, they reactivate the body's immune defenses against tumors.

ICIs have established themselves in numerous tumor types-from melanomas to lung and kidney carcinomas to tumor entities defined essentially by high mutational burden-they offer significant survival benefits.

Radiology plays a central role in the management of these therapies, as phenomena such as pseudoprogression challenge the classic RECIST (response evaluation criteria in solid tumors) system, and early detection of immune-mediated side effects often precedes clinical manifestation in imaging.

The growing complexity of therapy requires radiologists to possess precise image interpretation, interdisciplinary collaboration, and knowledge of immunological principles, thus, enabling an improved prognosis for many tumor types.