Low clinical utility of global longitudinal strain in a real-world breast cancer population

Abstract Background The 2022 European Society of Cardiology (ESC) Cardio-Oncology guidelines recommend the use of global longitudinal strain (GLS) to detect mild asymptomatic cancer therapy related cardiac dysfunction (ma-CTRCD). However, it remains unknown how to best manage these patients in order to prevent clinically significant CTRCD. Purpose To assess the course and outcomes of breast cancer patients meeting criteria for ma-CTRCD. Methods Echocardiograms and medical records were assessed for breast cancer patients receiving trastuzumab or an anthracycline, who underwent serial echocardiographic monitoring, including routine GLS. CTRCD was defined as an absolute decline in LVEF of >10% to <50%. ma-CTRCD was defined as a relative decline in average GLS of >15%, in the absence of significant LVEF decline. Normal was defined as no significant change in LVEF or GLS during cancer therapy. Clinical and echocardiographic course post ma-CTRCD detection was assessed. Baseline risk factors were compared between the three groups. Results 878 echocardiograms from 258 patients were analysed. GLS analysis was available in 76% of echocardiograms. CTRCD occurred in 23 (9%) and ma-CTRCD in 63 (24%). Only eight ma-CTRCD patients had management altered (cancer therapy withheld/ceased in three and heart failure medication commenced in six). Only two ma-CTRCD patients subsequently developed CTRCD, and GLS improved in 74%. Compared to the normal group (172, 67%), at baseline the ma-CTRCD group had higher average GLS (-21.8 vs -19.4, p<0.0001) and less borderline/abnormal average GLS (4% vs 36%, p<0.004). Conclusion Isolated declines in GLS are common and may have low clinical utility in preventing CTRCD. The findings support ESC guideline recommendations that cancer therapy should not be withheld in these patients. Those with higher baseline GLS may be more prone to clinically insignificant declines in GLS during cancer therapy.