Cardiotoxicity of the antiproliferative compound fluorouracil

Chemotherapy-related cardiotoxicity and its symptoms in patients with breast cancer: a scoping review

BACKGROUND

Chemotherapy-related cardiotoxicity is a significant concern because it is a major cause of morbidity. This study aimed to provide in-depth information on the symptoms of chemotherapy-related cardiotoxicity (CRCT) by exploring literature that concurrently reports the types and symptoms of CRCT in patients with breast cancer.

METHODS

A scoping review was performed according to an a priori protocol using the Joanna Briggs Institute's guidelines. The participants were patients with breast cancer. The concept was the literature of specifically reported symptoms directly matched with CRCT and the literature, in English, from 2010, and the context was open. The search strategy included four keywords: "breast cancer," "chemotherapy," "cardiotoxicity," and "symptoms." All types of research designs were included; however, studies involving patients with other cancer types, animal subjects, and symptoms not directly related to CRCT were excluded. Data were extracted and presented including tables and figures.

RESULTS

A total of 29 articles were included in the study, consisting of 23 case reports, 4 retrospective studies, and 2 prospective studies. There were no restrictions on the participants' sex; however, all of them were women, except for one case report. The most used chemotherapy regimens were trastuzumab, capecitabine, and doxorubicin or epirubicin. The primary CRCT identified were myocardial dysfunction and heart failure, followed by coronary artery disease, pulmonary hypertension, and other conditions. Major tests used to diagnose CRCT include echocardiography, electrocardiography, serum cardiac enzymes, coronary angiography, computed tomography, and magnetic resonance imaging. In all case reports, CRCT was diagnosed through an incidental checkup according to the patient's symptom presentation; however, only 10 of these studies showed a baseline checkup before chemotherapy. The five most common CRCT symptoms were dyspnea, chest pain, peripheral edema, fatigue, and palpitations, which were assessed by patient-reported symptom presentation rather than using a symptom assessment tool. Dyspnea with trastuzumab treatment and chest pain with capecitabine treatment were particularly characteristic. The time for first symptom onset after chemotherapy ranged from 1 hour to 300 days, with anthracycline-based regimens requiring 3-55 days, trastuzumab requiring 60-300 days, and capecitabine requiring 1-7 days.

CONCLUSIONS

This scoping review allowed data mapping according to the study design and chemotherapy regimens. Cardiac assessments for CRCT diagnosis were performed according to the patient's symptoms. There were approximately five types of typical CRCT symptoms, and the timing of symptom occurrence varied. Therefore, developing and applying a CRCT-specific and user-friendly symptom assessment tool are expected to help healthcare providers and patients manage CRCT symptoms effectively.

Capecitabine-induced-coronary-vasospasm leading to polymorphic ventricular tachycardia and cardiac arrest

Capecitabine, a pro-drug of 5-fluorouracil, is commonly used in the treatment of breast and colorectal cancer. Its side effects, including nausea, vomiting, diarrhea, fatigue, loss of appetite, and bone marrow suppression, are well recognized. However, coronary vasospasm represents a less commonly recognized but significant complication of fluoropyrimidine-based therapies such as capecitabine. Proposed mechanisms for this adverse effect complication include direct endothelium-independent vasoconstriction, activation of protein kinase C, and activation of the cyclooxygenase pathway. In this report, we present a case of capecitabine-induced coronary vasospasm leading to progressive, focal ST-elevations, myocardial ischemia, and subsequently polymorphic ventricular tachycardia. These events were captured on telemetry, in a male in his early 40s, diagnosed with stage IIIB sigmoid colon cancer. Notably, the patient had no pre-existing coronary artery disease or other cardiovascular risk factors. Upon diagnosis, the patient was initiated on a calcium channel blocker, verapamil, to mitigate further coronary vasospasm events. After thorough discussions that prioritized the patient's input and values, an implantable cardioverter-defibrillator was placed subcutaneously. Following discharge, the patient restarted capecitabine therapy along with verapamil prophylaxis and did not experience any subsequent shocks from his ICD as assessed during his outpatient follow-up visits. This case emphasizes the need to involve patients in decision-making processes, especially when managing unexpected and serious complications, to ensure treatments align with their quality of life and personal preferences.

Cardiotoxicity of anti-cancer drugs: cellular mechanisms and clinical implications

Cardio-oncology is an emerging field that seeks to enhance quality of life and longevity of cancer survivors. It is pertinent for clinicians to understand the cellular mechanisms of prescribed therapies, as this contributes to robust understanding of complex treatments and off-target effects, improved communication with patients, and guides long term care with the goal to minimise or prevent cardiovascular complications. Our aim is to review the cellular mechanisms of cardiotoxicity involved in commonly used anti-cancer treatments and identify gaps in literature and strategies to mitigate cardiotoxicity effects and guide future research endeavours.

An integrative review of nonobvious puzzles of cellular and molecular cardiooncology

Oncologic patients are subjected to four major treatment types: surgery, radiotherapy, chemotherapy, and immunotherapy. All nonsurgical forms of cancer management are known to potentially violate the structural and functional integrity of the cardiovascular system. The prevalence and severity of cardiotoxicity and vascular abnormalities led to the emergence of a clinical subdiscipline, called cardiooncology. This relatively new, but rapidly expanding area of knowledge, primarily focuses on clinical observations linking the adverse effects of cancer therapy with deteriorated quality of life of cancer survivors and their increased morbidity and mortality. Cellular and molecular determinants of these relations are far less understood, mainly because of several unsolved paths and contradicting findings in the literature. In this article, we provide a comprehensive view of the cellular and molecular etiology of cardiooncology. We pay particular attention to various intracellular processes that arise in cardiomyocytes, vascular endothelial cells, and smooth muscle cells treated in experimentally-controlled conditions in vitro and in vivo with ionizing radiation and drugs representing diverse modes of anti-cancer activity.

Reintroduction of 5-Fluorouracil Post-cardiac Arrest Secondary to Chemotherapy-Induced Cardiotoxicity

5-fluorouracil (5-FU) has been known to have cardiotoxic side effects, including coronary vasospasm, myocardial infarctions, heart failure, arrhythmias, and cardiac arrest. These cases have been reported in patients with either known coronary disease or known risk factors. In cases of acute cardiotoxicity, cessation of fluoropyrimidines is recommended, and reintroduction of the medication is generally avoided. We present a case of a young patient with no known risk factors for coronary disease, who presented with an acute cardiac arrest suspected secondary to vasospasm from the administration of 5-FU for the treatment of rectal cancer and was successfully maintained on treatment with 5-FU post-arrest after transitioning from an infusion to bolus administration.

Fluoropyrimidine‑induced cardiotoxicity in colorectal cancer patients: a prospective observational trial (CHECKPOINT)

Fluoropyrimidines (FP) are the backbone chemotherapy in colorectal cancer (CRC) treatment; however, their use is associated with cardiotoxicity, which is underreported. In the present study, it was aimed to prospectively determine the incidence rates and related risk factors of FP‑induced cardiotoxicity (FIC) in CRC patients and at identifying predictive biomarkers. A total of 129 consecutive previously untreated CRC patients underwent active cardiological monitoring, including 5‑items simplified questionnaire on symptoms, electrocardiogram (ECG) and plasma sample collection during FP chemotherapy. FIC was defined as the presence of ECG alterations and/or the arising of at least one symptom of chest pain, dyspnoea, palpitations or syncope. The primary objective was the evaluation of FIC incidence. Secondary objectives were the correlation of FIC with well‑known cardiological risk factors and the identification of circulating biomarkers (serum levels of troponin I, pro hormone BNP; miRNA analysis) as predictors of FIC. A total of 20 out of 129 (15.5%) patients experienced FIC. The most common symptoms were dyspnoea (60%) and chest pain (40%), while only 15% of patients presented ECG alterations, including one acute myocardial infarction. Retreatment with FP was attempted in 90% of patients with a favourable outcome. Despite 48% of patients having cardiological comorbidities, an increased FIC was not observed in this subgroup. Only the subgroup of females with the habit of alcohol consumption showed an increased risk of FIC. None of the circulating biomarkers evaluated demonstrated a clinical utility as FIC predictors. FIC can be an unexpected, life‑threatening adverse event that can limit the subsequent treatment choices in patients with CRC. In this prospective study, well‑known cardiological comorbidities were not related to higher FIC risk and circulating biomarkers predictive of toxicity could not be found. With careful monitoring, mainly based on symptoms, almost all patients completed the FP treatment.

The puzzling clinical presentation of fluoropyrimidines cardiotoxicity

The cardiotoxicity of fluoropyrimidines (FP) [5-Fluorouracil and Capecitabine] is often reported as acute cardiac ischemia with rest typical angina, signs of ischemia at electrocardiogram (ECG), and ventricular kinetics abnormalities. However, silent ischemia, effort-related toxicity, and ventricular arrhythmias (VA) have been also described. The aim of this study is to report a consecutive series of 115 patients with FP cardiotoxicity observed in a single center both within clinical prospective studies and during the clinical routine. The clinical presentation widely varied as regards symptoms, ECG abnormalities, and clinical outcomes. We report also the strategies used to prevent cardiotoxicity in a subgroup of 35 patients who continued o rechallenged FP therapy after cardiotoxicity. In nearly half of the patients, the cardiotoxicity was triggered by physical effort. Typical angina was rare: the symptoms were absent in 51% of cases and were atypical in half of the other cases. ST-segment elevation and VA were the most frequent ECG abnormality; however, ST segment depression or negative T waves were the only abnormalities in 1/3 of the cases. Troponins essays were often within the normal limits, even in presence of extensive signs of ischemia. The most effective strategy to prevent cardiotoxicity at rechallenge was reducing FP dosage and avoiding physical effort. Anti-ischemic therapies were not always effective. Raltitrexed was a safe alternative to FP. Fluoropyrimidine cardiotoxicity shows a wide variety of clinical presentations in real life, from silent ischemia to atypical symptoms, acute coronary syndrome, left ventricular dysfunction (LVD), VA, or complete atrio-ventricular block. Physical effort is the trigger of cardiotoxicity in nearly half of the cases. The recognition of cardiotoxicity cannot rely on symptoms only but requires an active screening with ECG and stress test in selected cases.

Endothelial dysfunction as a complication of anti-cancer therapy

Recent strides in anti-cancer therapeutics have improved longevity and led to a growing population of cancer survivors, who are increasingly likely to die of other causes. Treatment-induced cardiotoxicity is a complication of several therapeutic agents with acute and long-term consequences for cancer patients. Vascular endothelial dysfunction is a precursor and hallmark of ischemic coronary disease and may play a role in anti-cancer therapy-induced cardiotoxicity. This review summarizes clinical evidence for endothelial dysfunction following anti-cancer therapy and extends the discussion to include the impact of therapeutic agents on conduit arteries and the microcirculation. We highlight the role of innate immune system activation and cross-talk between inflammation and oxidative stress as pathogenic mechanisms underlying anti-cancer therapy-induced vascular toxicity. Understanding the impact of anti-cancer agents on the vascular endothelium will inform therapeutic approaches to prevent or reverse treatment-induced cardiotoxicity and may serve as an important tool to predict, monitor, and prevent adverse cardiovascular outcomes in patients undergoing treatment.

Capecitabine-Associated Coronary Vasospasm and Cardiac Arrest

Capecitabine is a prodrug of fluorouracil that specifically targets cancer cells, commonly used as monotherapy for metastatic breast and colorectal cancer. Its side effects include nausea, diarrhea, vomiting, abdominal pain, anorexia, palmar-plantar erythrodysesthesia, anemia, and hyperbilirubinemia. Rarely, this chemotherapy agent has been associated with cardiotoxicity, including cardiac arrest, likely secondary to coronary vasospasm. This case report serves to highlight the unfortunate case of a 32-year-old female who suffered a ventricular fibrillation cardiac arrest three days after initiating capecitabine therapy.

Breast Cancer and the Cardiovascular Disease: A Narrative Review

Breast cancer is the most common malignancy affecting females worldwide and is also among the top causes of all cancer-related deaths. Cardiovascular disease (CVD) is known to have the highest rate of mortality in women. There are several risk factors for both CVD and breast cancer that overlap, such as diet, smoking, and obesity, and also the current breast cancer treatment has a significant detrimental effect on cardiovascular health in general. Patients with exposure to potentially cardiotoxic treatments, including anthracyclines, trastuzumab, and radiation therapy, are more likely to develop CVD than non-cancer controls. Early detection and treatment may reduce the risk of the development of cardiac morbidity and mortality and would increase the number of breast cancer survivors. This article provides a comprehensive overview of breast cancer, identifies shared risk factors among breast cancer and CVD, and the cardiotoxic effects of therapy. It also reviews possible prevention and treatment of CVD in breast cancer patients and reviews literature about chemoprevention of cardiac disease in the setting of breast cancer treatment.

The efficacy and safety of cardio-protective therapy in patients with 5-FU (Fluorouracil)-associated coronary vasospasm

Background

Coronary vasospasm is a known side effect of 5-FU (fluorouracil) therapy. Beyond switching to non-5FU-based chemotherapy, there are no established treatments for 5-FU associated coronary vasospam. Our objective was to assess the safety and efficacy of re-challenge with 5-FU after pre-treatment with calcium channel blockers (CCBs) and long-acting nitrates among patients 5-FU associated coronary vasospasm.

Methods

We conducted a retrospective study of patients with 5-FU coronary vasospasm at a single academic center. By protocol, those referred to cardio-oncology received pre-treatment with either combination [nitrates and CCBs] or single-agent therapy [nitrates or CCBs]) prior to re-challenge with 5-FU. Our primary outcome was overall survival. Other important outcomes included progression-free survival and safety.

Results

Among 6,606 patients who received 5-FU from January 2001 to Dec 2020, 115 (1.74%) developed coronary vasospasm. Of these 115 patients, 81 patients continued 5-FU therapy, while 34 stopped. Of the 81 who continued, 78 were referred to cardio-oncology and prescribed CCBs and/or nitrates prior to subsequent 5-FU, while the remaining 3 continued 5-FU without cardiac pre-treatment. Of the 78, 56.4% (44/78) received both nitrates and CCBs, 19.2% (15/78) received CCBs alone, and 24.4% (19/78) received nitrates alone. When compared to patients who stopped 5-FU, those who continued 5-FU after pre-treatment (single or combination therapy) had a decreased risk of death (HR 0.42, P = 0.005 [95% CI 0.23–0.77]) and a trend towards decreased cancer progression (HR 0.60, P = 0.08 [95% CI 0.34–1.06]). No patient in the pre-treatment group had a myocardial infarct after re-challenge; however, chest pain (without myocardial infarction) recurred in 19.2% (15/78) among those who received cardiac pre-treatment vs. 66.7% (2/3) among those who did not (P = 0.048). There was no difference in efficacy or the recurrence of vasospasm among patients who received pre-treatment with a single agent (nitrates or CCBs) or combination therapy (14.7% (5/34) vs. 25.0% (11/44), P = 0.26).

Conclusion

Re-challenge after pre-treatment with CCBs and nitrates guided by a cardio-oncology service was safe and allowed continued 5-FU therapy.

5-Fluorouracil, capecitabine and vasospasm: a scoping review of pathogenesis, management options and future research considerations

BACKGROUND

5-Fluorouracil (5-FU) is a widely used chemotherapeutic agent that can cause cardiotoxicity manifesting, among others, as chest pain. Capecitabine is an oral prodrug of 5-FU, with reported preferential activation in malignant cells that may also cause cardiotoxic reactions. Standard treatment of 5-FU and capecitabine induced chest pain with vasodilators is mostly effective, but there are several cases of patients unresponsive to these agents.

METHODS

We performed a PubMed search on 31st May 2020. We used a three keyword search strategy using Boolean search operators. More specifically, we included fluorouracil or 5-FU or capecitabine and chest pain or angina and mechanism or treatment or management. We included primary reports of clinical and non-clinical data, as well as systematic reviews. Narrative reviews, expert opinions, letters to the editor and other forms of non-primary literature were excluded.

RESULTS

Our search yielded a total of 1595 reports. Of these, 1460 were narrative reviews or irrelevant to the topic and were excluded. A total of 135 reports were used for our review. We used 81 reports for data extraction, which included 13 clinical trials, 4 retrospective reports, 61 case reports, and 3 systematic reviews.

CONCLUSION

We report the incidence and predisposing factors, the value of available diagnostic procedures, and standard medical and invasive treatments. We also speculate on the potential benefit of arginine as a promising option both in prevention as well as treatment of 5-FU-induced chest pain. Finally, gaps of evidence are identified and proposals are made in terms of future research.

Risk for Myocardial Infarction Following 5-Fluorouracil Treatment in Patients With Gastrointestinal Cancer

Background

Myocardial infarction is a cardiac adverse event associated with 5-fluorouracil (5-FU). There are limited data on the incidence, risk, and prognosis of 5-FU-associated myocardial infarction.

Objectives

The aim of this study was to examine the risk for myocardial infarction in patients with gastrointestinal (GI) cancer treated with 5-FU compared with age- and sex-matched population control subjects without cancer (1:2 ratio).

Methods

Patients with GI cancer treated with 5-FU between 2004 and 2016 were identified within the Danish National Patient Registry. Prevalent ischemic heart disease in both groups was excluded. Cumulative incidences were calculated, and multivariable regression and competing risk analyses were performed.

Results

A total of 30,870 patients were included in the final analysis, of whom 10,290 had GI cancer and were treated with 5-FU and 20,580 were population control subjects without cancer. Differences in comorbid conditions and select antianginal medications were nonsignificant (P > 0.05 for all). The 6-month cumulative incidence of myocardial infarction was significantly higher for 5-FU patients at 0.7% (95% CI: 0.5%-0.9%) versus 0.3% (95% CI: 0.3%-0.4%) in population control subjects, with a competing risk for death of 12.1% versus 0.6%. The 1-year cumulative incidence of myocardial infarction for 5-FU patients was 0.9% (95% CI: 0.7%-1.0%) versus 0.6% (95% CI: 0.5%-0.7%) among population control subjects, with a competing risk for death of 26.5% versus 1.4%. When accounting for competing risks, the corresponding subdistribution hazard ratios suggested an increased risk for myocardial infarction in 5-FU patients, compared with control subjects, at both 6 months (hazard ratio: 2.10; 95% CI: 1.50-2.95; P < 0.001) and 12 months (hazard ratio: 1.39; 95% CI: 1.05-1.84; P = 0.022).

Conclusions

Despite a statistically significantly higher 6- and 12-month risk for myocardial infarction among 5-FU patients compared with population control subjects, the absolute risk for myocardial infarction was low, and the clinical significance of these differences appears to be limited in the context of the significant competing risk for death in this population.

Potential role of epicardial adipose tissue as a biomarker of anthracycline cardiotoxicity

Background

We investigated the radiodensity of epicardial (EAT), subcutaneous (SAT), and visceral adipose tissue (VAT) before and after treatment with anthracyclines in a population of breast cancer (BC) patients, and in controls not treated with anthracyclines, to detect a potential role of EAT density as a biomarker of changes related to chemotherapy cardiotoxicity.

Methods

We reviewed BC patients treated with anthracyclines who underwent CT before (CT-t₀) and after (CT-t₁) chemotherapy, and age- and sex-matched controls who underwent two CT examinations at comparable intervals. On non-contrast scans, EAT was segmented contouring the pericardium and thresholding between -190 and -30 Hounsfield units (HU), and SAT and VAT were segmented with two 15-mm diameter regions of interest thresholded between -195 and -45 HU.

Results

Thirty-two female patients and 32 controls were included. There were no differences in age (p = 0.439) and follow-up duration (p = 0.162) between patients and controls. Between CT-t₀ and CT-t₁, EAT density decreased in BC patients (-66 HU, interquartile range [IQR] -71 to -63 HU, to -71 HU, IQR -75 to -66 HU, p = 0.003), while it did not vary in controls (p = 0.955). SAT density increased from CT-t₀ to CT-t₁ in BC patients (-107 HU, IQR -111 to -105 HU, to -105 HU, IQR -110 to -100 HU, p = 0.014), whereas it did not change in controls (p = 0.477). VAT density did not vary in either BC patients (p = 0.911) or controls (p = 0.627).

Conclusions

EAT density appears to be influenced by anthracycline treatment for BC, well known for its cardiotoxicity, shifting towards lower values indicative of a less active metabolism.

Cardiotoxicity of Fluoropyrimidines: Epidemiology, Mechanisms, Diagnosis, and Management

Cancer is a growing public health problem; it is responsible annually for millions of deaths worldwide. Fluoropyrimidines are highly effective and commonly prescribed anti-neoplastic drugs used in a wide range of chemotherapy regimens against several types of malignancies. 5-fluorouracil and its prodrugs affect neoplastic cells in multiple ways by impairing their proliferation, principally through the inhibition of thymidylate synthase. Fluoropyrimidine-induced cardiotoxicity was described more than 50 years ago, but many details such as incidence, mechanisms, and treatment are unclear and remain disputed. Severe cardiotoxicity is not only life-threatening, but also leads to withdrawal from an optimal chemotherapy regimen and decreases survival rate. Differences in the frequency of cardiotoxicity are explained by different chemotherapy schedules, doses, criteria, and populations. Proposed pathophysiological mechanisms include coronary vasospasm, endothelial damage, oxidative stress, Krebs cycle disturbances, and toxic metabolites. Such varied pathophysiology of the cardiotoxicity phenomenon makes prevention and treatment more difficult. Cardiovascular disturbances, including chest pain, arrhythmias, and myocardial infarction, are among the most common side effects of this class of anti-neoplastic medication. This study aims to summarize the available data on fluoropyrimidine cardiotoxicity with respect to symptoms, incidence, metabolism, pathophysiological mechanism, diagnosis, management, and resistance.

Causes of Death After Colorectal Cancer Diagnosis: A Population-Based Study

Background: Non-cancer causes of death in patients with colorectal cancer (CRC) have not received much attention until now. The purpose of the current study is to investigate the non-cancer causes of death in patients with CRC at different periods of latency.

Methods: Eligible patients with CRC were included from the Surveillance, Epidemiology, and End Results (SEER) database, and standardized mortality ratios (SMRs) were calculated using the SEER*Stat software 8.3.8.

Results: A total of 475,771 patients with CRC were included, of whom 230,841 patients died during the follow-up period. Within 5 years, CRC was the leading cause of death. Over time, non-cancer causes of death account for an increasing proportion. When followed up for more than 10 years, non-cancer deaths accounted for 71.9% of all deaths worldwide. Cardiovascular diseases were the most common causes of non-cancer deaths, accounting for 15.4% of the total mortality. Patients had a significantly higher risk of death from septicemia within the first year after diagnosis compared with the general population (SMR, 3.39; 95% CI, 3.11–3.69). Within 5–10 years after CRC diagnosis, patients had a significantly higher risk of death from diabetes mellitus (SMR, 1.27; 95% CI, 1.19–1.36). During the course of more than 10 years, patients with CRC had a significantly higher risk of death from atherosclerosis (SMR 1.47; 95% CI, 1.11–1.9).

Conclusions: Although CRC has always been the leading cause of death in patients with CRC, non-cancer causes of death should not be ignored. For patients with cancer, we should not only focus on anti-tumor therapies but also pay attention to the occurrence of other risks to prevent and manage them in advance.

The Incidence, Risk Factors, and Outcomes With 5-Fluorouracil-Associated Coronary Vasospasm

Background

Coronary vasospasm is a recognized side effect of 5-fluorouracil (5-FU). There are limited and conflicting data on the incidence, risk factors, and prognostic effect of 5-FU–associated vasospasm.

Objectives

This study sought to assess the incidence, risk factors, and prognostic implications of 5-FU coronary vasospasm among patients receiving 5-FU regimens at a single tertiary care center.

Methods

The study conducted a retrospective analysis of all patients who received 5-FU at a single academic center from January 2009 to July 2019. Vasospasm was defined as the occurrence of a typical chest pain syndrome in the presence of 5-FU. The presence of associated electrocardiogram changes or elevated biomarkers was used to further confirm the diagnosis. Patients with vasospasm were compared with patients treated with 5-FU without vasospasm in a 1:2 ratio. Data regarding demographics, medical history, and follow-up were collected by manual chart review.

Results

From approximately 4,019 individual patients who received 5-FU from 2009 to 2019 at a single center, 87 (2.16%) developed vasospasm. Patients who developed vasospasm were younger (age 58 ± 13 years vs. 64 ± 13 years; p = 0.001) and were less likely to have any cardiovascular risk factors (70.1% vs. 84.5%; p = 0.007). Patients with vasospasm and patients without vasospasm were otherwise similar in terms of types of cancer, stage of cancer, sex, and race. There was no significant difference in progression-free survival, overall mortality or cancer specific mortality between patients who developed vasospasm versus those who did not.

Conclusions

In a large, single-center report of 5-FU–associated vasospasm, patients who developed vasospasm were younger, had lower rates of traditional cardiovascular risk factors, and had no significant difference in progression-free or overall survival compared with those who did not develop vasospasm.

Capecitabine-mediated heart failure in colorectal cancer: a case series

BACKGROUND

Capecitabine is a pyrimidine antimetabolite that inhibits thymidylate synthase and is commonly used in the treatment of colorectal cancer. Adverse cardiac side effects are reported in 1-18% of patients receiving Capecitabine. The most commonly proposed mechanism of cardiotoxicity in the setting of Capecitabine use is vasospasm of the coronary arteries. However, cardiotoxicity can also present as an acute coronary syndrome, arrhythmia, hypertension, and/or sudden cardiac death. Profound non-vasospastic cardiotoxicity is rare.

CASE SUMMARY

We describe two cases of acute heart failure leading to cardiogenic shock in patients shortly after exposure to Capecitabine. Both patients did not demonstrate the characteristic transient ST elevation seen in patients with coronary artery vasospasms secondary to Capecitabine. Both patients required admission to the Acute Cardiac Care Unit requiring vasopressor and inotropic support. Thorough diagnostic investigations including echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography did not identify infarction, myocarditis, or any infiltrative process to explain their symptoms. Both patients had complete resolution of cardiac function, with no long-term sequalae.

DISCUSSION

In patients receiving Capecitabine, reversible heart failure leading to cardiogenic shock should be considered as a potential cardiotoxic side effect.

5-FU Cardiotoxicity: Vasospasm, Myocarditis, and Sudden Death

PURPOSE OF REVIEW

5-fluorouracil (5-FU) is one of the most common causes of cardiotoxicity associated with chemotherapy. The manifestations of 5-FU cardiotoxicity are diverse, and there are no established clinical guidelines addressing the diagnosis and management of this condition. Here we summarize the mechanistic and clinical data available to guide clinicians in caring for patients with suspected 5-FU cardiotoxicity.

RECENT FINDINGS

The decision to resume 5-FU treatment in patients with suspected cardiovascular toxicity remains challenging. Testing for predisposing genetic variants may be helpful, particularly in patients with other signs of 5-FU toxicity. Uridine triacetate is a recently approved antidote that can improve clinical outcomes in patients with life-threatening fluoropyrimidine cardiotoxicity. 5-FU cardiotoxicity remains poorly understood, with limited mechanistic or prospective clinical trial data available to define risk factors or effective management strategies. Risk stratification and therapeutic decisions should be individualized, based on the risk-benefit ratio of continuing 5-FU therapy for each patient.

Vascular effects of cancer treatments

Chemotherapy, alone or in association with radiation therapy, has represented the cornerstone of cancer treatment for decades. However, in the last several years, an unprecedented progress in the understanding of cancer biology and the discovery of novel therapeutic targets have led to a paradigm shift in the management of patients with neoplastic diseases. The introduction of tyrosine kinase inhibitors, vascular endothelial growth factor pathway inhibitors, immunomodulatory agents, proteasome inhibitors, immune checkpoint inhibitors, and chimeric antigen receptor T cells, among others, has been associated with prolonged survival in many forms of cancer. A common feature of both chemotherapy and novel cancer treatments is the frequent occurrence of vascular toxicity, mainly mediated by injury to the endothelium. While the mechanisms may vary between agents, the clinical manifestations may overlap and range from hypertension, vasospastic and thrombotic arterial events (myocardial ischemia and infarction, peripheral ischemia, and limb gangrene), venous thromboembolism (deep vein thrombosis and pulmonary embolism) to capillary leak syndrome. Therefore, the effective management of patients with cancer requires a multidisciplinary team approach in which oncologist and cardiovascular medicine specialists work together to prevent, detect, and minimize acute vascular toxicity and long-term consequences of cancer therapy.

5-Fluorouracil Response Prediction and Blood Level-Guided Therapy in Oncology: Existing Evidence Fundamentally Supports Instigation

5-Fluorouracil (5-FU) response prediction and therapeutic drug monitoring (TDM) are required to minimize toxicity while preserving efficacy. Conventional 5-FU dose normalization uses body surface area. It is characterized by up to 100-fold interindividual variability of pharmacokinetic (PK) parameters, and typically >50% of patients have plasma 5-FU concentrations outside the optimal range. This underscores the need for a different dose rationalization paradigm, hence there is a case for 5-FU TDM. An association between 5-FU PK parameters and efficacy/toxicity has been established. It is believed that 5-FU response is enhanced and toxicity is reduced by PK management of its dosing. The area under the concentration-time curve is the most relevant PK parameter associated with 5-FU efficacy/toxicity, and optimal therapeutic windows have been proposed. Currently, there is no universally applied a priori test for predicting 5-FU response and identifying individuals with an elevated risk of toxicity. The following two-step strategy: prediction of response/toxicity and TDM for subsequent doses seems plausible. Approximately 80% of 5-FU is degraded in a three-step sequential metabolic pathway. Dihydropyrimidine dehydrogenase (DPD) is the initial and rate-limiting enzyme. Its deficiency can cause toxicity with standard 5-FU doses. DPD also metabolizes uracil (U) into 5,6-dihydrouracil (UH2). The UH2/U ratio is an index of DPD activity and a credible biomarker of response and toxicity. This article outlines the UH2/U ratio as a parameter for 5-FU response/toxicity prediction and highlights key studies emphasizing the value of 5-FU TDM. Broad application of 5-FU response/toxicity prediction and blood level-guided therapy remains unmet, despite ever-increasing clinical interest. Considered collectively, existing evidence is compelling and fundamentally supports universal instigation of response/toxicity prediction and TDM.

Cardio-Oncology: Vascular and Metabolic Perspectives: A Scientific Statement From the American Heart Association

Cardio-oncology has organically developed as a new discipline within cardiovascular medicine as a result of the cardiac and vascular adverse sequelae of the major advances in cancer treatment. Patients with cancer and cancer survivors are at increased risk of vascular disease for a number of reasons. First, many new cancer therapies, including several targeted therapies, are associated with vascular and metabolic complications. Second, cancer itself serves as a risk factor for vascular disease, especially by increasing the risk for thromboembolic events. Finally, recent data suggest that common modifiable and genetic risk factors predispose to both malignancies and cardiovascular disease. Vascular complications in patients with cancer represent a new challenge for the clinician and a new frontier for research and investigation. Indeed, vascular sequelae of novel targeted therapies may provide insights into vascular signaling in humans. Clinically, emerging challenges are best addressed by a multidisciplinary approach in which cardiovascular medicine specialists and vascular biologists work closely with oncologists in the care of patients with cancer and cancer survivors. This novel approach realizes the goal of providing superior care through the creation of cardio-oncology consultative services and the training of a new generation of cardiovascular specialists with a broad understanding of cancer treatments.

Fluoropyrimidine-Associated Cardiotoxicity: A Retrospective Case-Control Study

BACKGROUND

The fluoropyrimidines, 5-fluorouracil (5-FU) and capecitabine, are commonly used chemotherapeutic agents that have been associated with coronary vasospasm.

METHODS

In this retrospective case-control study, we identified patients at our institution who received 5-FU or capecitabine in 2018. We compared characteristics of patients who experienced cardiotoxicity with controls. We described phenotypes and outcomes of cardiotoxic cases.

RESULTS

We identified 177 patients who received fluoropyrimidines. After adjudication, 4.5% of the cohort met the criteria for cardiovascular toxicity. Coronary artery disease was more common among cases than controls (38% vs. 7%, p < .05). There was also a trend toward increased prevalence of cardiovascular risk factors in cases compared with controls. Most cardiotoxic cases had chest pain, although a minority of cases presented with nonischemic cardiomyopathy.

CONCLUSION

Cardiotoxicity phenotypes associated with fluoropyrimidine use are not limited to coronary vasospasm. Cardiac risk factors and ischemic heart disease were highly prevalent among patients with cardiotoxicity.

Acute reversible left ventricular systolic dysfunction associated with 5-fluorouracil therapy: a rare and increasingly recognised cardiotoxicity of a commonly used drug

5-Fluorouracil (5-FU) is the third most common chemotherapeutic agent for treating solid cancers and the second most common to cause cardiotoxicity. We present a rare case of acute reversible severe left ventricular systolic dysfunction associated with 5-FU. A 54-year-old woman with a history of stage IV gastric cancer presented with features of transient ischaemic attack after receiving the first dose of FLOT (5-FU, leucovorin, oxaliplatin and docetaxel). During the diagnostic workup, it was found that her ejection fraction was severely reduced to 15% with features of global hypokinesis, which later improved back to 65% within 13 days. These cases challenge our current understanding of the underlying mechanisms of this cardiotoxicity. Additionally, even though the patient did not experience any cardiac symptoms, it is important to monitor these patients closely as they are at high risk for fatal complications like arrhythmia and thrombus formation.

5-FU induced cardiotoxicity: case series and review of the literature

Background

5-Fluorouracil (5-FU) is an antimetabolite chemotherapy used for a variety of solid tumors. It has the potential to cause a wide spectrum of cardiotoxicity, ranging from asymptomatic electrocardiographic changes to cardiomyopathy and subsequent cardiac failure. Main body of the abstract: We present two descriptive cases of new-onset severe cardiomyopathy induced by 5-FU followed by a review of the literature.

Conclusion

Our case series emphasizes the importance of early recognition of this rare complication and prompt cessation of 5-FU, as cardiac dysfunction in this context is potentially reversible.

Fluoropyrimidine-Associated Cardiotoxicity

Fluoropyrimidines are chemotherapeutic agents that confer great benefit to many patients with solid tumors, but their use is often limited by cardiotoxicity. The incidence and precise mechanisms of cardiotoxicity remain uncertain. Clinical presentations of fluoropyrimidine toxicity are varied and include chest pain, myocardial infarction, acute cardiomyopathy, arrhythmia, cardiogenic shock, and sudden cardiac death. Proposed mechanisms include coronary vasospasm, coronary endothelial dysfunction, direct myocardial toxicity, myocarditis, and Takotsubo cardiomyopathy. Therapeutic and prophylactic interventions primarily target coronary vasospasm as the underlying cause. Prospective studies are needed to develop evidence-based approaches to cardioprotection in patients receiving fluoropyrimidines.

Cardiovascular complications of metastatic colorectal cancer treatment

Colorectal cancer (CRC) is the third most common malignancy in men and the second in women and the fourth cause of cancer death. Survival rates decrease greatly according to the stage of the disease at the time of diagnosis. Approximately 50% of CRC patients will develop metastatic disease (mCRC) with survival and prognosis depending on the timing of metastatic development, and the localization and number of metastatic sites. The overall survival of patients with mCRC has been significantly improved over the last years from approximately 12 to more than 30 months with the integration of multiple cytotoxic agents and targeted therapies. The optimal therapeutic strategy depends on the general condition and performance status of the patient, the resectability or not of metastases and the mutational status of the tumor in terms of BRAF and RAS. Cardiovascular (CV) complications of mCRC treatment may develop peri-operatively and mostly during chemotherapy. During first-line treatment, 90% of patients experience more than one adverse event (AE) and 39% of them are CV. Angina, hypertension, arrhythmias, arterial and venous thrombotic events (VTEs), heart failure (HF) and death are the main CV events resulting from the applied chemotherapy regimens. Cardio-oncology consultation for identification of high-risk patients, proper monitoring during and after therapy and timely intervention would allow the successful prevention and the efficient management of cardiotoxicity, rendering the patient able to receive the indicated cancer therapy and improving the overall outcome.

Cancer Therapy-Related Cardiac Dysfunction: An Overview for the Clinician

Cancer therapy-related cardiac dysfunction (CTRCD) is one of the most feared and undesirable side effects of chemotherapy, occurring in approximately 10% of the patients. It can be classified as direct (dose-dependent vs dose-independent) or indirect, either case being potentially permanent or reversible. Risk assessment, recognition, and prevention of CTRCD are crucial.

Takotsubo cardiomyopathy in cancer patients

Background

Cancer is a chronic condition that induces significant emotional and physical stress, which may increase the risk for developing Takotsubo cardiomyopathy (TCM).

Main body

Takotsubo cardiomyopathy, also known as stress cardiomyopathy, is a clinical syndrome that generally presents as chest pain mimicking acute coronary syndrome or as an acute heart failure characterized by severe left ventricular systolic dysfunction in response to emotional, physical, or medical stress. The potential triggers for Takotsubo syndrome in cancer patients include the emotional turmoil of a cancer diagnosis, the inflammatory state of the cancer itself, and the physical stress of cancer surgery, systemic anti-neoplastic therapy, and radiation treatment. TCM is becoming increasingly recognized among patients with cancer and has been associated with adverse outcomes in this patient population. In this study, we searched the Pubmed database using keywords “Takotsubo cardiomyopathy”, “cancer”, and “anti-neoplastic therapy” to review case reports of Takotsubo syndrome occurring in oncologic patients after systemic anti-neoplastic therapy. Clinical presentation, electrocardiogram, laboratory data, transthoracic echocardiogram and coronary angiogram results, and patient outcomes were collected and analyzed.

Conclusion

Patients with cancer are at an elevated risk for developing stress cardiomyopathy, and it is important to know which cancer drugs have been associated with the development of the Takotsubo syndrome.

Efficacy and Cardiotoxic Safety Profile of Raltitrexed in Fluoropyrimidines-Pretreated or High-Risk Cardiac Patients With GI Malignancies: Large Single-Center Experience

BACKGROUND

Gastrointestinal (GI) cancer patients may not be considered for therapy with fluoropyrimidines (FPs) because of previous cardiovascular (CV) toxicity or preexisting risk factors; such patients may benefit from raltitrexed-based therapy.

PATIENTS AND METHODS

Patient, tumor, and treatment characteristics, as well as clinical outcomes of all consecutively treated patients with raltitrexed at the Royal Marsden Hospital between October 1998 and July 2011 were examined. GI cancer patients who developed CV toxicity as a result of FPs and those with significant CV risk factors receiving raltitrexed were included in this analysis.

RESULTS

A total of 247 patients (155 and 92 with CV FP-related CV toxicities and significant CV risk factors, respectively) treated with raltitrexed alone or in combination were examined after a median follow-up of 47.1 months. CV toxicity profiles of patients receiving capecitabine (n = 110) and 5-fluorouracil (n = 45) were largely similar. Of raltitrexed-treated patients, 13 (5%) experienced CV toxicities and 1 (< 0.1%) died as a result of myocardial infarction. The median progression-free survival (PFS) and overall survival (OS) were 36.0 months (95% confidence interval [CI], 26.5-48.6) and 44.3 months (95% CI, 33.1-56.8), respectively. The 5-year survival for early stage GI malignancies (n = 140) was 62.0% (95% CI, 50.1-71.9). Median PFS and OS were not reached in this group (interquartile range = 38.4 months to NR); median PFS and OS for advanced GI malignancies (n = 107) were 18.8 (95% CI, 11.9-25.7) and 23.7 months (95% CI, 17.0-26.9), respectively.

CONCLUSION

A raltitrexed-based regimen is well-tolerated therapy with comparable efficacy to FPs in patients with GI malignancies with significant CV toxicities or risk factors.

Role of Urotensin-2 in 5-Fluorouracil-Related Arterial Vasoconstriction in Cancer Patients

BACKGROUND

The aim of this study was to identify the possible relationship of 5-fluorouracil (5-FU)-related arterial vasoconstriction with urotensin-2 (UT-2), which has a high potential as an endogenic vasoconstrictor.

METHODS

We assigned the patients to 1 of 3 groups. Patients in group 1 received a bolus of 5-FU, those in group 2 a continuous infusion (CI) of 5-FU, and those in group 3 no 5-FU, which was also a control group. Pre- and post-treatment UT-2 levels and brachial arterial diameters were measured and recorded in all patients.

RESULTS

132 patients were included in the study. Pre- and post-treatment brachial artery diameters were similar in all groups: in group 1 (3.28 ± 0.52 vs. 3.25 ± 0.44 mm, p = 0.740), in group 2 (3.57 ± 0.47 vs. 3.46 ± 0.45 mm, p = 0.441) and in the control group (3.51 ± 0.52 vs. 3.25 ± 0.44 mm, p = 0.818). Pre- and post-treatment UT-2 levels were significantly different in each group: in group 1 (39.5 ± 30.9 vs. 56.7 ± 27.1 ng/ml, p = 0.0001), in group 2 (37.7 ± 33.7 vs. 62.5 ± 37.7 ng/ml, p = 0.0001) and in the control group (52.9 ± 40.2 vs. 60.8 ± 40.7 ng/ml, p = 0.006).

CONCLUSION

Our findings suggest that UT-2 has a high potential as a vasoconstrictor agent in our bodies and its level increases through a bolus or CI 5-FU. Increased UT-2 levels are likely to play a role in 5-FU-related cardiac toxicity pathogenesis.

5-fluorouracil and cardiotoxicity: a review

Fluoropyrimidines such as 5-fluorouracil (5-FU) form the foundation of a wide variety of chemotherapy regimens. 5-FU is in fact the third most commonly used chemotherapeutic agent in the treatment of solid malignancies across the world. As with all chemotherapy, balancing the potential benefits of therapy against the risks of drug-related toxicity is crucial when clinicians and patients make shared decisions about treatment. 5-FU is the second most common chemotherapeutic drug associated with cardiotoxicity after anthracyclines, which can manifest as chest pain, acute coronary syndrome/myocardial infarction or death. Nevertheless a widespread appreciation of 5-FU-related cardiotoxicity and its implications is lacking amongst clinicians. In this review, we outline the incidence, possible risk factors, and likely pathophysiological mechanisms that may account for 5-FU-related cardiotoxicity and also highlight potential management strategies for this poorly understood clinical entity.

Acute Cardiotoxicity during Capecitabine Treatment: A Case Report

Capecitabine (Xeloda®, Roche, Monza), a fluoropyrimidine carbamate, is an orally administered drug that delivers fluorouracil (5-FU) selectively to the tumor. The drug has demonstrated activity in metastatic breast cancer, pancreatic cancer and colorectal cancer.

In this case report the authors describe an unusually and reversible cardiac side effect which occurs to 39-year-old patient treated with capecitabine 2000 mg/m2/day for advanced gastric cancer.

It is important to note that the safety data from clinical trials indicate that capecitabine has a toxicity profile typical of infused fluoropyrimidines. However, none of the studies described cardiac side effects.

Contrasting sirtuin and poly(ADP-ribose)polymerase activities of selected 2,4,6-trisubstituted benzimidazoles

Both sirtuin and poly(ADP-ribose)polymerase (PARP) family of enzymes utilize NAD⁺ as co-substrate. Inhibitors of sirtuins and PARPs are important tools in drug discovery as they are reported to be linked to multiple diseases such as cancer. New potent sirtuin inhibitors (2,4,6-trisubstituted benzimidazole) were discovered from reported PARP inhibitor scaffold. Interestingly, the synthesized compounds have contrasting sirtuin and PARP-1 inhibitory activities. We showed that modification on benzimidazoles may alter their selectivity toward sirtuin or PARP-1 enzymes. This offers an opportunity for further discovery and development of new promising sirtuin inhibitors. Molecular docking studies were carried out to aid the rationalization of these observations. Preliminary antiproliferative studies of selected compounds against nasopharyngeal cancer cells also showed relatively promising results.

Fluoropyrimidine-induced cardiac toxicity: challenging the current paradigm

BACKGROUND

Fluoropyrimidine chemotherapy [5-fluorouracil (5-FU) and capecitabine] are commonly used agents in the treatment of various solid malignancies. However, their use has been limited by cardiac toxicity, presenting as a wide spectrum of asymptomatic (e.g., EKG changes) and symptomatic (e.g., chest pain) manifestations related to coronary vasospasm leading to myocardial ischemia. Historically, patients with suspected coronary vasospasm have been treated with traditional acute ischemic workup and various combinations of anti-anginal therapies. In addition, most patients typically are not rechallenged with fluoropyrimidine after experiencing initial cardiovascular side-effects with resulting interruption of planned chemotherapy regimens.

METHODS

We report a case series of 11 consecutive patients in a single-center with suspected fluoropyrimidine-induced coronary vasospasm who were successfully rechallenged with the culprit drug to allow for planned chemotherapy completion. Our protocol utilized rechallenge with bolus infusional regimen of intravenous fluoropyrimidine chemotherapy and oral capecitabine with cardioprotective pretreatment with two calcium blockers and long-acting oral nitrate therapy.

RESULTS

We were successfully able to continue and complete the previously planned first-line chemotherapy regimen for all 11 patients with minimal therapeutic interruption. There have been no cardiac events or evidence of recurrent coronary spasm after completion of therapy with discontinuation of prophylactic medications upon therapy completion.

CONCLUSIONS

We report a single-institution experience of successful rechallenge with fluoropyrimidines with careful cardiac monitoring and the combined use of calcium channel blockers and long-acting nitrates. With further study, this algorithm can be used to safely continue fluoropyrimidines, a potentially curative regimen in the treatment of many solid tumors.

Fluoropyrimidine-Induced Cardiotoxicity: Manifestations, Mechanisms, and Management

Fluoropyrimidines-5-fluorouracil (5-FU) and capecitabine-have been implicated as cardiotoxic chemotherapy agents. This rare, albeit potentially serious toxicity has been described in nearly four decades of case reports, case series, and in vitro modeling; however, there is a paucity in clinical trials and prospective analyses focused on cardioprotective strategies and cardiotoxic surveillance of these agents. While much attention has focused on the well-known cardiac toxicity of anthracyclines and monoclonal antibody agents such as trastuzumab, fluoropyrimidines remain one of the most common causes of chemotherapy-associated cardiotoxicity. The introduction of capecitabine, an oral prodrug of 5-FU, has made the treatment of solid tumors more convenient along with a subsequent rise in documented cardiotoxic cases. This review discusses the symptomatology, clinical manifestations, and proposed molecular mechanisms that attempt to describe the heterogeneous spectrum of fluoropyrimidine-induced cardiotoxicity. Four case examples showcasing the varied manifestations of cardiotoxicity are presented. Finally, several proposed management strategies for cardiotoxicity and post-hospital course precautions are discussed.

Drug-Induced Takotsubo Cardiomyopathy

BACKGROUND

The most plausible hypothesis for takotsubo cardiomyopathy (TCM) is a catecholamine surge. Direct administration of catecholamines or medications causing catecholamine surge is frequently used in clinical practice.

METHODS

A Medline/PubMed database search was conducted for case reports or series of drug-induced TCM. All reported cases of drug-induced TCM were systemically identified and analyzed.

RESULTS

We identified 157 cases of drug-induced TCM. Fifty-seven (36.3%) cases were related to the administration of exogenous catecholamines. In 50 (31.9%) other cases, there was potential adrenergic effect. This included drugs with adrenergic vasoconstriction properties (3.2%), hyperadrenergic state due to alcohol or opioid withdrawal (7.7%), inhibitors of catecholamine reuptake (14.7%), anaphylactic reaction that is accompanied by catecholamine release (3.2%), and psychological or somatic stress coinciding with the administration of a drug that was thought to be the culprit (3.2%). Overall, 68.2% of these drug-induced TCM cases were catecholamine related. In 14 (8.9%) cases, the likely etiology of cardiomyopathy was chemotherapy-induced coronary vasospasm.

CONCLUSION

Our systematic review showed that over two-thirds of drug-induced TCM cases were due to direct or indirect catecholamine stimulation. The lowest effective dose and shortest duration of catecholamines should be utilized, and alternative therapies should be considered if feasible.

FOLFOX Induced Takotsubo Cardiomyopathy Treated with Impella Assist Device

Chemotherapy induced cardiotoxicity is becoming increasingly prevalent with several new agents being used recently. The incidence of Takotsubo cardiomyopathy due to 5-fluorouracil based chemotherapeutic regimens like FOLFOX is not uncommon. It is also seen with platinum based chemotherapy. Most of these patients have reversible cardiotoxicity and the cardiac function recovers within a short period with supportive treatment. Here we have a patient who presented with cardiogenic shock after 5 days of receiving FOLFOX regimen for colorectal adenocarcinoma. She was treated with a percutaneous left ventricular assist device, Impella CP, for hemodynamic support with excellent outcome.

Cardiac lesions induced by 5-fluorouracil in the rabbit

Cardiotoxicity is a rare, but well-recognized complication of treatments with the anti-cancer drug 5-fluorouracil (5FU). The underlying mechanism, however, is not fully elucidated. A spasm of the coronary arteries is often considered to be the leading cause of myocardial ischemia and decreased contractility associated with 5FU. As spasm cannot account for all reported adverse cardiac effects, the present study was undertaken to search for alternative mechanisms. Groups of six rabbits were given either a single intravenous dose of 50 mg/kg 5FU or four intravenous doses of 15 mg/kg 5FU at 7-day intervals. A third group served as control. The heart was removed shortly after death or scheduled sacrifice of the animals, to perform macroscopic and microscopic examinations of the heart and to evidence apoptosis by the TUNEL method. Following a single dose of 50 mg/kg 5FU, all animals rapidly developed a massive hemorrhagic myocardial infarct with spasms of the proximal coronary arteries. Repeated infusions of 15 mg/kg 5FU induced left ventricular hypertrophy, foci of myocardial necrosis, thickening of intra-myocardial arterioles, and disseminated apoptosis in myocardial cells of the epicardium, as well as endothelial cells of the distal coronary arteries. These results indicate that a spasm of the coronary arteries is not the only mechanism of 5FU cardiotoxicity, and that apoptosis of myocardial and endothelial cells can result in inflammatory lesions mimicking toxic myocarditis.

A systematic review of raltitrexed-based first-line chemotherapy in advanced colorectal cancer

Raltitrexed is a thymidylate synthase inhibitor belonging to the antimetabolite class of cytotoxic drugs. It is also effective in colorectal cancer (CRC) both as a single agent and in combination with other drugs, in particular in those patients with cardiologic risk factors or previous cardiotoxicity. The efficacy of first-line raltitrexed-based chemotherapy containing oxaliplatin (TOMOX) and irinotecan (TOMIRI) was investigated in this systematic review. Studies that enrolled advanced CRC patients for first-line therapy with TOMOX/TOMIRI combinations were identified using electronic databases (Pubmed, SCOPUS, Web of Science, EMBASE, and the Cochrane Library). A systematic analysis was carried out using Comprehensive Meta Analysis (version 2.2.064) software to calculate the pooled response rate and 95% confidence limits. The median pooled overall survival and progression-free survival were also calculated. Results for TOMOX and TOMIRI studies were compared using the two-sided Student's t-test. We tested for significant heterogeneity using Cochran's χ-test and I index. Twelve studies published between 2001 and 2012 were eligible for this analysis and a total of 735 patients were enrolled in these studies. The overall response rate was 40% (95% confidence interval 34-46%): 43.9% for TOMOX and 34.1% for TOMIRI arms. The weighted median overall survival and progression-free survival times were 14.6 and 6.7 months, respectively. Neutropenia and liver toxicity were more frequent with TOMOX, whereas neutropenia and diarrhea were more frequent with TOMIRI. However, compared with historical FOLFOX and FOLFIRI trials, raltitrexed-based doublets are associated with less neutropenia and gastrointestinal toxicity and uncommon cardiotoxicity. TOMOX and TOMIRI doublets are active as first-line chemotherapy for advanced CRC and seem useful in particular when the use of 5-fluorouracil is contraindicated for cardiac comorbidity.

Capecitabine for treating head and neck cancer

INTRODUCTION

With an increasing incidence, over half a million cases of head and neck cancer (HNC) are diagnosed annually worldwide. Various chemotherapeutic agents are utilized to achieve adequate locoregional control. Cisplatin, fluorouracil (FU), and taxanes are often used to treat HNC but these regimens have shown high toxicity and poor patient compliance. Capecitabine is an orally administered prodrug that is preferentially converted to FU in tumor cells in comparison to normal cells.

AREA COVERED

In this review, the authors evaluate the role of capecitabine in radical and palliative settings either alone or in combination with other chemotherapeutic drugs in the management of HNC. In addition, metabolic conversion, pharmacokinetics, pharmacodynamics, and toxicity profile of capecitabine are discussed.

EXPERT OPINION

Various phase II trials conducted on capecitabine in the management of recurrent HNC have shown comparable results and tolerable toxic effects especially in pre-treated fragile patients. Capecitabine, used in induction or concurrent settings in the radical management of locoregionally advanced HNC, have also shown promising results. Randomized trials are needed to validate the role of capecitabine in the management of HNC.

Effects of 5-fluorouracil on morphology, cell cycle, proliferation, apoptosis, autophagy and ROS production in endothelial cells and cardiomyocytes

Antimetabolites are a class of effective anticancer drugs interfering in essential biochemical processes. 5-Fluorouracil (5-FU) and its prodrug Capecitabine are widely used in the treatment of several solid tumors (gastro-intestinal, gynecological, head and neck, breast carcinomas). Therapy with fluoropyrimidines is associated with a wide range of adverse effects, including diarrhea, dehydration, abdominal pain, nausea, stomatitis, and hand-foot syndrome. Among the 5-FU side effects, increasing attention is given to cardiovascular toxicities induced at different levels and intensities. Since the mechanisms related to 5-FU-induced cardiotoxicity are still unclear, we examined the effects of 5-FU on primary cell cultures of human cardiomyocytes and endothelial cells, which represent two key components of the cardiovascular system. We analyzed at the cellular and molecular level 5-FU effects on cell proliferation, cell cycle, survival and induction of apoptosis, in an experimental cardioncology approach. We observed autophagic features at the ultrastructural and molecular levels, in particular in 5-FU exposed cardiomyocytes. Reactive oxygen species (ROS) elevation characterized the endothelial response. These responses were prevented by a ROS scavenger. We found induction of a senescent phenotype on both cell types treated with 5-FU. In vivo, in a xenograft model of colon cancer, we showed that 5-FU treatment induced ultrastructural changes in the endothelium of various organs. Taken together, our data suggest that 5-FU can affect, both at the cellular and molecular levels, two key cell types of the cardiovascular system, potentially explaining some manifestations of 5-FU-induced cardiovascular toxicity.