Immunotherapy in Lung Cancer and the Role of Imaging

Lung cancer is the leading cause of cancer-related mortality and accounts for more deaths than breast, prostate, and colon cancers combined. Traditionally, treatment options have included surgery, chemotherapy, and radiation therapy. Continual advances in the characterization of lung cancer have resulted in the development of effective immunotherapies. These agents help the immune system recognize tumors as foreign, stimulate the immune system, and relieve the inhibition that allows the growth and spread of cancer. Conventional response criteria such as the World Health Organization criteria and Response Evaluation Criteria in Solid Tumors (RECIST) have been used extensively in clinical trials; however, these guidelines have been optimized for use with traditional cytotoxic chemotherapy. Data from clinical trials employing immunotherapy has shown that unique responses may be seen with these agents that are not fully captured by conventional response criteria. In response to these observations, several modified criteria have been developed for use with immunotherapy, including immune-related response criteria, immune-related RECIST, and immune RECIST. As the use of immunotherapy continues to grow, there is increasing recognition of immune-related adverse events, which may manifest on imaging examinations.