Abstract
In recent years, systemic cancer treatment has been revolutionized with the advent
of immunotherapy, which utilizes the body's immune system to target cancer cells and
results in unique and novel imaging patterns of cancer response and therapy-associated
toxicities. Hyperprogression is defined as a rapid tumor progression after treatment
initiation. In contrast, pseudoprogression is defined as a tumor response after an
initial increase in tumor burden, or appearance of new tumor lesions, and observed
in <10% of patients undergoing PD-1/PD-L1 immunotherapy. Since traditional radiological
strategies might not fully capture tumor response of patients receiving immunotherapy,
several efforts have been made to better quantify specific immuno-oncological imaging
patterns, including immune-related response criteria, immune-related RECIST, immunotherapy
RECIST, and modified RECIST. These criteria account for potential pseudoprogression,
and thus may prevent preemptive immunotherapy cessation. Immunotherapy is also associated
with specific immune-related adverse events, including colitis (8–22% of patients),
hypophysitis (8–13%), pneumonitis (<4%), lymphadenopathy (5–7%), hepatitis (1–7%),
and pancreatitis (2%). Quantification of imaging studies using radiomic features has
shown promising results in immuno-oncology, including prediction of individual patient's
treatment response and survival, as well as characterization of tumoral expression
of immunotherapy-relevant targets.
Keywords
immunotherapy - imaging - radiomics
