Optimization of radiation target volume for locally advanced esophageal cancer in the immunotherapy era.

Introduction: Locally advanced esophageal cancer (EC) has poor prognosis. Preliminary clinical studies have demonstrated the synergistic efficacy of radiotherapy combined with immunotherapy in EC. Adjusting the radiotherapy target volume to protect immune function favors immunotherapy. However, there is no clear consensus on the exact definition of the EC target volume.

Areas covered: Preclinical studies have provided a wealth of information on immunotherapy combined with different radiotherapy modalities, and several clinical studies have evaluated the impact of immunotherapy combined with radiotherapy on locally advanced EC. Here, we illustrate the rational target volume delineation for radiotherapy in terms of patient prognosis, pattern of radiotherapy failure, treatment-related toxicities, tumor-draining lymph nodes, and systemic immunity and summarize the clinical trials of radiotherapy combined with immunotherapy in EC.

Expert opinion: We recommend applying involved-field irradiation (IFI) instead of elective nodal irradiation (ENI) for irradiated fields when immunotherapy is combined with chemoradiotherapy (CRT) for locally advanced EC. We expect that this target design will be evaluated in clinical trials to further explore more precise diagnostic modalities, long-term toxic responses, and quality of survival, and stratification factors for personalized treatment, and to provide more treatment benefits for patients.