Longitudinal Changes in QTc Interval in Cancer Patients After the Initiation of Systemic Therapy: Analysis of the ONCOECHO Study Cohort

Abstract

Simple Summary Some cancer treatments can affect the heart’s electrical activity and prolong the QT interval on an electrocardiogram, which may increase the risk of dangerous heart rhythm disturbances. However, the frequency and pattern of these changes in patients without known cardiovascular disease are not fully understood. This study investigated how the QT interval changes during the first year after starting systemic cancer treatment and explored which patients may be more likely to develop clinically relevant prolongation. The analysis included 291 patients with newly diagnosed cancer who underwent electrocardiographic assessment before treatment and during follow-up. The findings showed a modest overall increase in the corrected QT interval, while clinically important prolongation and serious ventricular arrhythmias were uncommon. Older age and higher QT measurements early in treatment were associated with greater risk. The results support individualized electrocardiographic monitoring and careful selection of the method used to assess QT duration.