Should a patient on ribociclib (Ribociclib), letrozole (Letrozole), and zoladex (Goserelin) receive a screening echocardiogram if asymptomatic?

Screening Echocardiogram for Asymptomatic Patients on Ribociclib, Letrozole, and Zoladex

Yes, asymptomatic patients on ribociclib should receive baseline and periodic screening echocardiograms due to the known cardiotoxic potential of CDK 4/6 inhibitors, particularly ribociclib's association with QTc prolongation and cardiac dysfunction. 1

Rationale for Cardiac Screening

Ribociclib carries specific cardiac risks that mandate surveillance even in asymptomatic patients:

• Ribociclib has a higher incidence of liver function test abnormalities and can cause QTc prolongation, requiring cardiac monitoring throughout treatment 2
• The American Society of Clinical Oncology recommends baseline echocardiographic assessment of left ventricular function before initiation of potentially cardiotoxic cancer treatment in all patients, irrespective of clinical history 1
• Two-dimensional echocardiography coupled with Doppler flow studies is the preferred imaging modality for monitoring asymptomatic patients receiving cardiotoxic therapies 1

Recommended Screening Protocol

Baseline Assessment:

• Obtain echocardiogram before starting ribociclib to establish baseline left ventricular ejection fraction (LVEF) and confirm baseline cardiac risk 1
• Normal baseline parameters: LVEF ≥50%, fractional shortening (FS) ≥30% 1

Ongoing Surveillance Strategy:

• For patients with normal baseline echocardiogram and no clinical risk factors, surveillance echocardiography should be considered during treatment 1
• The European Society of Cardiology recommends echocardiographic examination during treatment, though exact intervals are not firmly established 1
• More frequent surveillance may be considered for patients with abnormal baseline echocardiography (reduced or low normal LVEF, structural heart disease) or higher baseline clinical risk 1

Interpretation of Abnormal Findings

If screening reveals cardiac dysfunction, stratify by severity:

• LVEF ≥50%, FS ≥30% with other abnormalities: Consultation with cardiologist 1
• LVEF 45-49%, FS 25-29%: Consultation or referral to cardiologist; consider ACE inhibitor treatment with careful monitoring 1
• LVEF <45%, FS <25%: Referral to cardiologist; consider treatment with ACE inhibitor 1
• Cancer therapeutics-related cardiac dysfunction is defined as a decrease in LVEF >10 percentage points to a value below the lower limit of normal, confirmed by repeated imaging 2-3 weeks after initial finding 1

Critical Considerations Specific to This Regimen

Ribociclib's unique cardiac profile requires particular attention:

• Ribociclib may be prudently avoided in patients with cardiac morbidities or other risk factors for QTc prolongation, including drug interactions 2
• In patients with pre-existing cardiac conditions, alternative CDK 4/6 inhibitors (palbociclib or abemaciclib) may be preferred 2
• The combination of ribociclib with endocrine therapy (letrozole) showed manageable safety profile in clinical trials, but cardiac monitoring remains essential 3

Common Pitfalls to Avoid

• Do not assume absence of symptoms means absence of cardiac dysfunction: Patients may gradually decrease activity or attribute symptoms to non-cardiac causes, particularly elderly patients 4
• Ensure consistent imaging methodology: Use the same echocardiographic technology and analysis software to limit technical variability when comparing serial studies 1
• Do not rely solely on LVEF: Other echocardiographic parameters (diastolic function, global longitudinal strain) may provide valuable early information regarding cardiac function 1

Post-Treatment Surveillance

After completing ribociclib therapy:

• Survivors who completed treatment may be considered for follow-up surveillance echocardiography at 1 and 5 years after completion of cancer treatment 1
• Long-term surveillance should be considered for those who developed evidence of cardiotoxicity during treatment 1