Background and Importance Osimertinib is a tyrosine kinase inhibitor (TKI) indicated for the treatment of epidermal growth factor receptor mutated non-small-cell lung cancer (NSCLC). Despite a better safety profile than other TKIs for the same indication, osimertinib could produce some potentially fatal cardiotoxicity. However, the available evidence on cardiotoxicity in clinical practice is very limited.

Aim and Objectives To analyse the incidence of cardiotoxicity associated with osimertinib in the real clinical practice.

Material and Methods We conducted an observational cross-sectional study in a third-level hospital in Spain. We included all adult patients diagnosed with NSCLC treated with osimertinib between February 2018 and May 2021. We collected socio-demographic data and treatment characteristics, as well as cardiological history, all events of cardiac toxicity during treatment and other comorbidities. Descriptive statistical analysis was performed.

Results 33 patients were included, with a median age of 72.5 (interquartile range [IQR]= 62.2–81.0) years, and 63.6% were women. The indication for osimertinib was metastatic lung adenocarcinoma (32 patients, 96.7%) and epidermoid non-small-cell lung cancer (1 patient, 0.3%). It was used as the first-line of treatment in 39.4% of the patients and as the second-line or successive in 60.6% of them.

At the start of treatment, 57.6% of the patients had cardiovascular comorbidities. The most frequent comorbidites were arterial hypertension (48.5%), dyslipidemia (36.4%), and diabetes mellitus (12.1%), and one patient was diagnosed with congestive heart failure.

The median time on osimertinib treatment was 11.0 (IQR= 4.6–17) months. Of the 33 patients, 21.2% of patients had previous cardiac examinations before starting osimertinib treatment. During the treatment, 4 (12,1%) patients developed cardiac adverse reactions: 2 (6.1%) suffered a decrease in the Left Ventricular Ejection Fraction (LVEF), 1 (3.0%) experienced atypical chest pain, and 1 (3.0%) developed an increase in the D-dimer and hyperfibrinogenaemia. One of the patients with LVEF decreased required hospitalisation and invasive management. The rest of the cardiotoxicities were managed with dose reduction and conservative measures.

Conclusion and Relevance More than 10% of osimertinib-treated patients had cardiotoxicity. Of these, 25% required hospitalisation. Oncologists should always assess cardiac function at the start of osimertinib and during the follow-up.

Conflict of Interest No conflict of interest.