The definition of “cardiotoxicity” is not universally agreed upon. Due to the multidisciplinary aspect of cardio-oncology, many definitions originate from different specialties. The National Cancer Institute defines it as “the toxicity that affects the heart.”(6) This toxicity is not limited to the myocardium but also affects the pericardium, the endocardium, and coronary vasculature (7). Recently, the term cardiotoxicity has been used interchangeably with “Cancer Therapy Related Cardio-Vascular Toxicity” (CTR-CVT). This term includes CTRCD, which can be symptomatic HF or only asymptomatic drop in LVEF or GLS or biomarkers abnormalities; immuno-checkpoint inhibitors myocarditis, vascular toxicities (coronary artery disease, peripheral artery disease, thromboses, stroke or transient ischemic accidents), arterial hypertension or cardiac arrhythmias (QT prolongation, atrial fibrillation, supraventricular tachycardia). This definition is adopted by the ESC guidelines 2022 and was initially created by the International Cardio-Oncology Society (IC-OS) (8). Cardioprotective approaches to prevent CTR-CVT include concomitant strategies of cardiovascular disease and/or others specific to cancer and its therapy. Taking the multiple-hit model of HF as observation and extrapolating it to the CTRCD, patients with previous or subclinical cardiovascular risk factors will not tolerate additional injury due to less cardiac functional reserve (7). Thus, COC aims to reduce this risk associated with modifiable risk factors by providing strategies related to pharmacological and non-pharmacological approaches and ensuring the most cardio-protection and quality of life for these patients. It is crucial to sustain the collaboration between medical oncology/hematology, cardiology, and other healthcare professions charged with the care for cancer patients who have or are at risk of CTR-CVT to limit cancer treatment's short- and long-term effects.
The present study provides valuable insights into the characteristics and clinical outcomes of patients referred to a multidisciplinary COC in Lebanon. In this cohort, we focused on CTRCD.
The findings highlight the effectiveness of the clinic in managing impaired LVEF in cancer patients, with a significant proportion of patients achieving either full or partial recovery of LVEF. In contrast, most of the patients completed the desired therapy.
Thirty-one patients (77.5%) out of 40 who had a decrease in LVEF initially have recovered from this drop, whether having complete or partial recovery. This finding is particularly noteworthy, as it demonstrates that restoration of cardiac function is possible in a significant proportion of patients despite all the risk factors, especially with good risk stratification, protective measures, and close follow-ups. This recovery is associated with better clinical outcomes.
The interventions done during COC visits are based on evidence-based approaches and depend on patients’ tolerance. It was statistically significant that the drop in LVEF was worse in patients who were not started on the combination of ACEi and beta-blockers, with a p-value of 0.022. Recently, interim analysis results of a 4-arm, randomized trial (SAFE [Cardiotoxicity Prevention in Breast Cancer Patients Treated with Anthracyclines and/or Trastuzumab]) evaluating the effect of bisoprolol, ramipril, or their combination to reduce anthracycline-associated subclinical cardiac injury were published. These results included a 12-month follow-up period showing a statistically significant difference in LVEF reduction in patients in the placebo group compared to the ramipril, bisoprolol, and combination arms (9).
Other predictors that might be helpful from risk stratification are troponin level and N-terminal-pro-B type Natriuretic Peptide. Elevated levels of these markers at baseline were associated with worse outcomes, reflecting a worse cardiac reverse. Here comes the role of neurohormonal inhibition that modulates the response to injury rather than the cardiotoxic process. More data is required to stratify patients into risk categories and decide how aggressive the cardioprotective treatment should be (10).
The multidisciplinary care provided in the COC likely contributed to the observed improvements in LVEF. Optimization of cardiovascular risk factors, adjustment of cancer treatment regimens, and the use of cardioprotective medications are all essential components of the comprehensive care delivered by the clinic (11, 12). These interventions likely played an indispensable role in managing cardiovascular complications and promoting LVEF recovery (5). Furthermore, an adequate initial risk stratification and close follow-up lead to a better therapy completion rate and a low rate of discontinuation or interruption. In our study, treatment was discontinued only in 9 patients (8%). This shows that strict cardiac monitoring and appropriate cardiovascular therapy initiation or optimization warrant the majority of patients to maintain and complete their prescribed cancer therapy (13–15).
Patients are typically referred to cardiac-oncology clinics for various reasons, often associated with potential cardiotoxicities from cancer treatments. In our study, most referrals were pre-therapy assessments (31%), either before a bone marrow transplant or before starting a drug known to have cardiac toxicity. This approach reflects the preventive assessment needed for cancer patients and the need for risk stratification. The second most common reason for referral was a drop in the cardiac function. Monitoring for early cardiovascular symptoms detection is essential in oncologic treatment. Moreover, baseline risk stratification is crucial to identify patients at higher risk of developing cardiotoxicities. The process involves evaluating baseline cardiac function, cardiovascular risk factors, and cancer type and treatment that could be potentially cardiotoxic (5).
One of the challenges in Lebanon and the MENA region is lack of awareness among oncologists and cardiologists regarding the importance of cardio-oncology. This can lead to delayed referrals and inadequate monitoring. Facing these challenges should include access to specialized care clinics, continuous training and awareness for healthcare professionals, and spreading awareness on different levels to prevent missed opportunities for early intervention. Educational programs at all levels must be implemented. Patients should be educated about cancer treatment's potential cardiovascular side effects and encouraged to communicate any symptoms or concerns with their healthcare providers. Interdisciplinary collaboration is necessary between oncologists and cardiologists to enhance cancer patients' overall quality of care.
The findings of this study align with existing literature on the importance of cardio-oncology programs in managing cardiovascular health in cancer patients (16, 17). However, it is essential to consider the limitations of this study, including its retrospective design and the absence of a control group. A control group is necessary to assess the comparative effectiveness of the interventions provided in the cardiac-oncology clinic.
Future research should aim to address these limitations and explore the optimal strategies for managing impaired LVEF in cancer patients. Data on patient satisfaction and quality of life are essential and should be quality metrics for any intervention in the care of these patients. Prospective studies with larger sample sizes and control groups are needed to validate the effectiveness of multidisciplinary COC in diverse patient populations. Long-term follow-up studies can provide valuable insights into the durability of LVEF recovery and its impact on long-term outcomes, including overall survival and quality of life.