Cardiac radiosensitivity in the era of thoracic chemoradiotherapy and immunotherapy: a scoping review

Concurrent chemoradiotherapy followed by immune checkpoint inhibitor (ICI) consolidation is now the standard of care for unresectable stage III non-small-cell lung cancer (NSCLC) and is increasingly applied to other thoracic malignancies. Although survival outcomes have improved, concerns about cardiac toxicity have emerged, as both chemoradiotherapy and ICIs are independently cardiotoxic and their combined effects remain unclear. This scoping review first examines chemoradiotherapy-associated and ICI-associated cardiac toxicity separately, and then evaluates their convergence in combined chemoradiotherapy and ICI therapy. For this examination and evaluation, we draw on ten clinical studies, two reviews, and five preclinical reports that together address six key questions: (1) does ICI add cardiac risks to chemoradiotherapy, (2) does previous radiotherapy increase cardiac risks with ICI, (3) does ICI alter the radiosensitivity of cardiac subregions, (4) how should cardiac endpoints be defined, (5) can molecular or pharmacological interventions mitigate toxicity, and (6) what are the major risk factors and management strategies? We also highlight four major gaps: extension beyond NSCLC, long-term survivorship, the potential of advanced radiotherapy techniques, and the interplay between lymphopenia and cardiotoxicity. The convergence of chemoradiotherapy and ICIs represents a new cardiac risk profile. Addressing these questions through larger, long-term studies is essential to balance oncological efficacy with cardiovascular safety.