Electrocardiograms (ECGs) in phase I anticancer drug development: the MD Anderson Cancer Center experience with 8518 ECGs

Ventricular Arrhythmia in Cancer Patients: Mechanisms, Treatment Strategies and Future Avenues

Cardiovascular disease and cancer are the leading causes of morbidity and mortality in the US. Despite the significant progress made in cancer treatment leading to improved prognosis and survival, ventricular arrhythmias (VA) remain a known cardiovascular complication either exacerbated or induced by the direct and indirect effects of both traditional and novel cancer treatments. Although interruption of cancer treatment because of VA is rarely required, knowledge surrounding this issue is essential for optimising the overall care of patients with cancer. The mechanisms of cancer-therapeutic-induced VA are poorly understood. This review will discuss the ventricular conduction (QRS) and repolarisation abnormalities (QTc prolongation), and VAs associated with cancer therapies, as well as existing strategies for the identification, prevention and management of cancer-treatment-induced VAs.

Cancer Chemotherapy-Induced Sinus Bradycardia: A Narrative Review of a Forgotten Adverse Effect of Cardiotoxicity

Cardiotoxicity is a common adverse effect of anticancer drugs (ACDs), including the so-called targeted drugs, and increases morbidity and mortality in patients with cancer. Attention has focused mainly on ACD-induced heart failure, myocardial ischemia, hypertension, thromboembolism, QT prolongation, and tachyarrhythmias. Yet, although an increasing number of ACDs can produce sinus bradycardia (SB), this proarrhythmic effect remains an underappreciated complication, probably because of its low incidence and severity since most patients are asymptomatic. However, SB merits our interest because its incidence increases with the aging of the population and cancer is an age-related disease and because SB represents a risk factor for QT prolongation. Indeed, several ACDs that produce SB also prolong the QT interval. We reviewed published reports on ACD-induced SB from January 1971 to November 2020 using the PubMed and EMBASE databases. Published reports from clinical trials, case reports, and recent reviews were considered. This review describes the associations between ACDs and SB, their clinical relevance, risk factors, and possible mechanisms of onset and treatment.

Cardiometabolic risk in childhood cancer survivors

The Italian Cancer Registry Association has estimated that for the five-year period 2016-2020, in line with the previous five years, approximately 7,000 neoplasms have been diagnosed among children and 4,000 among adolescents. Leukemias, brain tumors and lymphomas together account for more than two-thirds of all pediatric cancers. Fortunately, the five-years survival rate has progressively improved reaching 80% thanks to the continuing improvement of therapeutic protocols but the vast majority of these cancer survivors will have at least one chronic health condition by 40 years of age. Long-term complications concern various organs and systems and have a multifactorial etiopathogenesis. Obesity, diabetes and metabolic syndrome represent chronic diseases that affect life expectancy. Cardiovascular risk partly linked to therapies and genetic susceptibility and partly linked to the presence of obesity, diabetes and metabolic syndrome predispose childhood cancer survivors to heart failure, coronary artery disease, valvular disease, arrhythmia. Hence the cardio- metabolic risk of childhood cancer survivors can have a significant impact on their lives, families, and on society at-large. It is therefore very important to know the risk factors that predispose to the development of cardio-metabolic pathologies in childhood cancer survivors, the possible primary and secondary prevention strategies, the methods of surveillance and the therapeutic approaches.

A unique window of opportunity for practical reform of cancer clinical trials

With rapid modifications in cancer clinical trial operations necessitated by the global pandemic over the last year, there is now an unprecedented opportunity to reform clinical research permanently and solidify innovative practices that have clearly been effective. On the basis of the authors' experience and recommendations from other institutions, a set of specific proposals for clinical trial reform are identified that can be implemented immediately by sponsors, regulators, and study sites. Improvements in clinical trial processes should include increased leverage of technology to facilitate remote trial activity and electronic documents, more efficient and effective communication of adverse event information, and better study design to optimize inclusion criteria, required research procedures, and data collection. The authors suggest that such reform will preserve patient safety and study integrity, address unnecessary and inefficient pre-pandemic constraints, improve access to clinical trials for patients, and speed improvements in cancer care.

ECG Markers of Cardiovascular Toxicity in Adult and Pediatric Cancer Treatment

When a cardiologist is asked to evaluate the cardiac toxic effects of chemotherapy, he/she can use several tools: ECG, echocardiography, coronary angiography, ventriculography, and cardiac MRI. Of all these, the fastest and easiest to use is the ECG, which can provide information on the occurrence of cardiac toxic effects and can show early signs of subclinical cardiac damage. These warning signs are the most desired to be recognized by the cardiologist, because the dose of chemotherapeutics can be adjusted so that the clinical side effects do not occur, or the therapy can be stopped in time, before irreversible side effects. This review addresses the problem of early detection of cardiotoxicity in adult and pediatric cancer treatment, by using simple ECG recordings.

Experience, Perceptions, and Recommendations Concerning COVID-19-Related Clinical Research Adjustments

BACKGROUND

During the COVID-19 public health emergency, the FDA and NIH altered clinical trial requirements to protect participants and manage study conduct. Given their detailed knowledge of research protocols and regular contact with patients, clinicians, and sponsors, clinical research professionals offer important perspectives on these changes.

METHODS

We developed and distributed an anonymous survey assessing COVID-19-related clinical trial adjustment experiences, perceptions, and recommendations to Clinical Research Office personnel at the Harold C. Simmons Comprehensive Cancer Center. Responses were compared using the Fisher exact test.

RESULTS

A total of 94 of 109 contacted research personnel (87%) responded. Among these individuals, 58% had >5 years' professional experience in clinical research, and 56% had personal experience with a COVID-19-related change. Respondents perceived that these changes had a positive impact on patient safety; treatment efficacy; patient and staff experience; and communication with patients, investigators, and sponsors. More than 90% felt that positive changes should be continued after COVID-19. For remote consent, telehealth, therapy shipment, off-site diagnostics, and remote monitoring, individuals with personal experience with the specific change and individuals with >5 years' professional experience were numerically more likely to recommend continuing the adjustment, and these differences were significant for telehealth (P=.04) and therapy shipment (P=.02).

CONCLUSIONS

Clinical research professionals perceive that COVID-19-related clinical trial adjustments positively impact multiple aspects of study conduct. Those with greatest experience-both specific to COVID-19-related changes and more generally-are more likely to recommend that these adjustments continue in the future.

Electrophysiologic Complications in Cancer Patients

In recent years, dramatic advances in both cancer diagnosis and treatment have led to significantly increased survival rates. As such, cardiovascular toxicities due to oncologic treatments are more frequently identified. Although heart failure and cardiomyopathy have historically been the cardiotoxicities most associated with cancer therapeutics, it is now recognized that all components of the cardiovascular system can be affected. In this review, we discuss electrophysiologic complications of cancer treatments, including atrial and ventricular tachyarrhythmias as well as bradyarrhythmias, and recommend a multidisciplinary approach with both cardiologists and oncologists to provide safe and effective care to these patients.

Oral Anticancer Therapy: Management of Drug Interactions

Oral anticancer therapy is increasingly integrated into the care of patients with cancer. Recognition and management of drug-drug interactions (DDIs) is critical to providing efficacious and safe anticancer treatment. DDIs with QTc-prolonging agents, anticoagulants, enzyme inducers and inhibitors, antidepressants, and acid suppressants are commonly encountered with anticancer therapies. Here, we review frequently observed DDIs and outline literature-supported suggestions for their management.

Management of cardiac disease in cancer patients throughout oncological treatment: ESMO consensus recommendations

Cancer and cardiovascular (CV) disease are the most prevalent diseases in the developed world. Evidence increasingly shows that these conditions are interlinked through common risk factors, coincident in an ageing population, and are connected biologically through some deleterious effects of anticancer treatment on CV health. Anticancer therapies can cause a wide spectrum of short- and long-term cardiotoxic effects. An explosion of novel cancer therapies has revolutionised this field and dramatically altered cancer prognosis. Nevertheless, these new therapies have introduced unexpected CV complications beyond heart failure. Common CV toxicities related to cancer therapy are defined, along with suggested strategies for prevention, detection and treatment. This ESMO consensus article proposes to define CV toxicities related to cancer or its therapies and provide guidance regarding prevention, screening, monitoring and treatment of CV toxicity. The majority of anticancer therapies are associated with some CV toxicity, ranging from asymptomatic and transient to more clinically significant and long-lasting cardiac events. It is critical however, that concerns about potential CV damage resulting from anticancer therapies should be weighed against the potential benefits of cancer therapy, including benefits in overall survival. CV disease in patients with cancer is complex and treatment needs to be individualised. The scope of cardio-oncology is wide and includes prevention, detection, monitoring and treatment of CV toxicity related to cancer therapy, and also ensuring the safe development of future novel cancer treatments that minimise the impact on CV health. It is anticipated that the management strategies discussed herein will be suitable for the majority of patients. Nonetheless, the clinical judgment of physicians remains extremely important; hence, when using these best clinical practices to inform treatment options and decisions, practitioners should also consider the individual circumstances of their patients on a case-by-case basis.

Emerging Challenges to the Safe and Effective Use of Methadone for Cancer-Related Pain in Paediatric and Adult Patient Populations

Methadone continues to be an important medication for the treatment of paediatric and adult cancer-related pain. Appropriate patient selection to ensure safe and effective treatment by a team of clinicians who appreciate and are familiar with methadone and its unique pharmacology is crucial. Unlike morphine and other more common opioids, methadone is purported to have involvement with delta-opioid receptor and higher affinity as an N-methyl-D-aspartate-receptor antagonist. Clinically this gives it the advantage of being effective for both nociceptive and neuropathic pain, but also may be useful in the setting of tolerance to other opioids. Methadone also comes in multiple available formulations that can be administrated through a variety of routes beyond the oral route. Challenges with methadone in treating cancer-related pain include drug interactions specifically as it relates to new targeted cancer therapies. Recent guidelines recommend electrocardiogram monitoring with methadone and there is potential for additive cardiac toxicity in the oncology setting. Appropriate dosing of methadone for pain management given age, organ dysfunction, and patients who are on methadone maintenance therapy are also key factors. This article aims to provide clinicians with evidence and clinical practice guidelines for safe and appropriate use of methadone including indication, initiation, and monitoring given its complexity for management of pain in the dynamic oncology setting.

QTc Interval-Prolonging Medications Among Patients With Lung Cancer: Implications for Clinical Trial Eligibility and Clinical Care

BACKGROUND

Concomitant medication use, including agents that prolong the corrected QT (QTc) interval, can result in the exclusion of patients with cancer from clinical trials. To estimate the potential effects on accrual, we determined the prevalence of QTc-prolonging medication prescriptions in a national patient cohort.

PATIENTS AND METHODS

We identified adult patients in the Veterans Affairs system with a diagnosis of lung cancer from 2003 to 2016. The use of QTc interval-prolonging medications and risk category were obtained from CredibleMeds. We calculated the prevalence of prescriptions for QTc-prolonging medications with a known or possible risk of torsade de pointes in the 3 months up to and including the date of cancer diagnosis. The rates across patient groups were compared using χ² test.

RESULTS

A total of 280,068 patients were included in the present study. The mean age was 70 years, 98% were male, and 72% were white. Overall, 28.4% had been prescribed a QTc-prolonging medication, and 7.3% had been prescribed ≥2 in the 3 months before the cancer diagnosis. The most commonly prescribed QTc-prolonging medications were antimicrobial agents (14.0%), psychiatric agents (10.2%), antiemetic agents (2.6%), and cardiac medications (1.7%). Excluding the antimicrobial agents, 18.4% of the patients had been prescribed a QTc-prolonging medication.

CONCLUSIONS

A substantial proportion of individuals with lung cancer will be prescribed QTc-prolonging medications. These prescriptions can limit patients' eligibility for clinical trials and complicate the administration of standard cancer therapies. Further research into the actual clinical risks and optimal management of QTc-prolonging medications in cancer populations is warranted.

Cardio-Oncology Fellowship Training and Education

PURPOSE OF REVIEW

With the rapid development of novel cancer therapeutics and the growing number of cancer survivors, there is significant demand for cardio-oncology experts to care for these patients. As such, it has become increasingly necessary to develop formalized training in the field of cardio-oncology. This review will focus on the current state of cardio-oncology education, with recommendations for the development of dedicated cardio-oncology fellowships.

RECENT FINDINGS

Cardio-oncology fellowships should be affiliated with high-volume centers that have established cardio-oncology clinical and research programs with dedicated cardio-oncology faculty. Several recent publications have proposed recommendations to develop uniform cardio-oncology training standards, core curricula, and evaluation metrics. With the rapid evolution of the field and the support of various profession organizations, the number and quality of dedicated cardio-oncology fellowship programs is expected to increase significantly. The adoption of defined training requirements and evaluation standards to measure competency will be essential to ensure the legitimacy and success of the field.

Incidence, Diagnosis, and Management of QT Prolongation Induced by Cancer Therapies: A Systematic Review

Background

The cardiovascular complications of cancer therapeutics are the focus of the burgeoning field of cardio‐oncology. A common challenge in this field is the impact of cancer drugs on cardiac repolarization (ie, QT prolongation) and the potential risk for the life‐threatening arrhythmia torsades de pointes. Although QT prolongation is not a perfect marker of arrhythmia risk, this has become a primary safety metric among oncologists. Cardiologists caring for patients receiving cancer treatment should become familiar with the drugs associated with QT prolongation, its incidence, and appropriate management strategies to provide meaningful consultation in this complex clinical scenario.

Methods and Results

In this article, we performed a systematic review (using Preferred Reporting Items of Systematic Reviews and Meta‐Analyses (PRISMA) guidelines) of commonly used cancer drugs to determine the incidence of QT prolongation and clinically relevant arrhythmias. We calculated summary estimates of the incidence of all and clinically relevant QT prolongation as well as arrhythmias and sudden cardiac death. We then describe strategies to prevent, identify, and manage QT prolongation in patients receiving cancer therapy. We identified a total of 173 relevant publications. The weighted incidence of any corrected QT (QTc) prolongation in our systematic review in patients treated with conventional therapies (eg, anthracyclines) ranged from 0% to 22%, although QTc >500 ms, arrhythmias, or sudden cardiac death was extremely rare. The risk of QTc prolongation with targeted therapies (eg, small molecular tyrosine kinase inhibitors) ranged between 0% and 22.7% with severe prolongation (QTc >500 ms) reported in 0% to 5.2% of the patients. Arrhythmias and sudden cardiac death were rare.

Conclusions

Our systematic review demonstrates that there is variability in the incidence of QTc prolongation of various cancer drugs; however, the clinical consequence, as defined by arrhythmias or sudden cardiac death, remains rare.

Modernizing Clinical Trial Eligibility Criteria: Recommendations of the American Society of Clinical Oncology–Friends of Cancer Research Organ Dysfunction, Prior or Concurrent Malignancy, and Comorbidities Working Group

Purpose

Patients with organ dysfunction, prior or concurrent malignancies, and comorbidities are often excluded from clinical trials. Excluding patients on the basis of these factors results in clinical trial participants who are healthier and younger than the overall population of patients with cancer.

Methods

ASCO and Friends of Cancer Research established a multidisciplinary working group that included experts in trial design and conduct to examine how eligibility criteria could be more inclusive. The group analyzed current eligibility criteria; conducted original data analysis; considered safety concerns, potential benefits, research, and potential hurdles of this approach through discussion; and reached consensus on recommendations regarding updated eligibility criteria that prioritize inclusiveness without compromising patient safety.

Results

If renal toxicity and clearance are not of direct treatment-related concern, then patients with lower creatinine clearance values of > 30 mL/min should be included in trials. Inclusion of patients with mild to moderate hepatic dysfunction may be possible when the totality of the available nonclinical and clinical data indicates that inclusion is safe. Ejection fraction values should be used with investigator assessment of a patient’s risk for heart failure to determine eligibility. Patients with laboratory parameters out of normal range as a result of hematologic disease should be included in trials. Measures of patient functional status should be included in trials to better assess fit versus frail patients.

Conclusion

Expanding inclusion of these patients will increase the number and diversity of patients in clinical trials and result in a more appropriate population of patients.

Broadening Eligibility Criteria to Make Clinical Trials More Representative: American Society of Clinical Oncology and Friends of Cancer Research Joint Research Statement

Purpose The primary purposes of eligibility criteria are to protect the safety of trial participants and define the trial population. Excessive or overly restrictive eligibility criteria can slow trial accrual, jeopardize the generalizability of results, and limit understanding of the intervention's benefit-risk profile. Methods ASCO, Friends of Cancer Research, and the US Food and Drug Administration examined specific eligibility criteria (ie, brain metastases, minimum age, HIV infection, and organ dysfunction and prior and concurrent malignancies) to determine whether to modify definitions to extend trials to a broader population. Working groups developed consensus recommendations based on review of evidence, consideration of the patient population, and consultation with the research community. Results Patients with treated or clinically stable brain metastases should be routinely included in trials and only excluded if there is compelling rationale. In initial dose-finding trials, pediatric-specific cohorts should be included based on strong scientific rationale for benefit. Later phase trials in diseases that span adult and pediatric populations should include patients older than age 12 years. HIV-infected patients who are healthy and have low risk of AIDS-related outcomes should be included absent specific rationale for exclusion. Renal function criteria should enable liberal creatinine clearance, unless the investigational agent involves renal excretion. Patients with prior or concurrent malignancies should be included, especially when the risk of the malignancy interfering with either safety or efficacy endpoints is very low. Conclusion To maximize generalizability of results, trial enrollment criteria should strive for inclusiveness. Rationale for excluding patients should be clearly articulated and reflect expected toxicities associated with the therapy under investigation.

Cardio-Oncology - A new subspecialty with collaboration at its heart

Cardio-Oncology is the care of cancer patients with cardiovascular disease, overt or occult, already established or acquired during treatment. Cancer patients can present with a variety of cardiovascular problems not all of which are directly related to cancer therapy (medications or radiotherapy). The cardiovascular problems of oncology patients can range from ischaemia to arrhythmias and can also include valve problems and heart failure. As such, within cardiology, teamwork is required with members of different cardiology subspecialties. The way forward will be to adopt a multidisciplinary approach to produce optimal individual care. Close collaboration between cardiology and oncology specialists in a Cardio-Oncology setting can make this happen.

Targeted Cancer Therapies and QT Interval Prolongation: Unveiling the Mechanisms Underlying Arrhythmic Complications and the Need for Risk Stratification Strategies

The care and treatment of cancer patients has significantly changed in the last decade with a remarkable shift towards novel targeted therapies. These promising new drugs may represent effective and potentially life-saving therapeutic options in cancer patients, but are also emerging in the cardiotoxicity scenario for their arrhythmogenic potential due to their QT-prolonging activity. In this article we review the mechanisms underlying drug-induced QT interval prolongation and the classes of anticancer-targeted therapies most frequently responsible for this adverse event, with a particular focus on tyrosine kinase-targeting molecules. Since up to 49 % of serious adverse drug reactions (ADRs) and 58 % of potentially fatal ADRs may not appear on initial drug safety labels, we also review and discuss data from the post-marketing VigiBase^® safety reporting system, the World Health Organization's global database of ADRs. Finally, we discuss arrhythmic risk stratification and prevention strategies in the complex multiple-risk setting of cancer patients, paying particular attention to drug-drug interactions with common antimicrobial, psychotropic and antiemetic supportive care, and we also provide an electrocardiographic QT monitoring algorithm for patients who are candidates for targeted cancer therapies.

Cardiotoxicity of antiemetic drugs in oncology: An overview of the current state of the art

PURPOSE

Cardiac complications in cancer patients have been a significant medical problem in the last few years. Cardiosafety profile of most novel approved drugs, in cancer patients, is required by regulatory authorities. Risk of proarrhythmic effect associated with a new drug, in fact, is usually evaluated with specific studies conducted in agreement with ICHE14 guidelines. In this overview, we detailed the cardio safety profile of antiemetic drugs. In particular, we focused on data of 5HT3-RA drugs used for prevention of chemotherapy-induced nausea and vomiting in the oncology setting.

METHODS

A literature search was conducted using the PubMed database to identify studies reporting arrhythmic complications of antiemetic drug used in oncology.

RESULTS AND CONCLUSION

Most of the antiemetic drugs have been approved by regulatory authorities when ICHE14 guidelines were not issued, so the cardiotoxicity of those drugs has been defined with the post-marketing authorization pharmacovigilance activity. We reviewed the cardiotoxicity data of major antiemetic and adjuvant agents, providing a general overview and recommendations about their use in medical oncology.

QT Prolongation and Oncology Drug Development

Many pharmaceutical agents interact with cardiac ion channels resulting in abnormal ventricular repolarization and prolongation of the QT interval. In rare circumstances, this has resulted in the development of the potentially life-threatening arrhythmia, torsades de pointes. It is recognized, however, that accurate measurement of the QT interval is challenging, and it is a poor predictor for the development of this arrhythmia. Nevertheless, QT interval monitoring is an essential part of pharmaceutical development, and significant increases in the QT interval may prevent a drug from gaining approval.

Cardiotoxicity of anticancer treatments

Patients with cancer can experience adverse cardiovascular events secondary to the malignant process itself or its treatment. Patients with cancer might also have underlying cardiovascular illness, the consequences of which are often exacerbated by the stress of the tumour growth or its treatment. With the advent of new treatments and subsequent prolonged survival time, late effects of cancer treatment can become clinically evident decades after completion of therapy. The heart's extensive energy reserve and its ability to compensate for reduced function add to the complexity of diagnosis and timely initiation of therapy. Additionally, modern oncological treatment regimens often incorporate multiple agents whose deleterious cardiac effects might be additive or synergistic. Treatment-related impairment of cardiac contractility can be either transient or irreversible. Furthermore, cancer treatment is associated with life-threatening arrhythmia, ischaemia, infarction, and damage to cardiac valves, the conduction system, or the pericardium. Awareness of these processes has gained prominence with the arrival of strategies to monitor and to prevent or to mitigate the effects of cardiovascular damage. A greater understanding of the mechanisms of injury can prolong the lives of those cured of their malignancy, but left with potentially devastating cardiac sequelae.

The prognostic significance of left ventricular ejection fraction in patients with advanced cancer treated in phase I clinical trials

BACKGROUND

New targeted agents may cause acute cardiac events. The purpose of our study was to investigate the incidence and the prognostic significance of left ventricular ejection fraction (LVEF) in phase I trials.

PATIENTS AND METHODS

Between October 2008 and September 2011, the records of 1166 consecutive patients with advanced cancer treated in the Phase I Clinic who underwent echocardiography were retrospectively reviewed.

RESULTS

Most of the patients were White (78%), and the most common tumor types were colorectal cancer and melanoma. Of 1166 patients, 177 (15.2%) patients had an LVEF of <50%. No difference in overall survival (OS) between patients with LVEF ≥ 50% and patients with LVEF < 50% was seen (median OS 7.4 versus 7.0 months, P = 0.84). Patients with LVEF ≤ 35% had shorter survival compared with those with LVEF between 35% and 50% (median 4.2 versus 8.0 months; P = 0.005). In multivariate analysis of patients with LVEF < 50%, independent factors predicting longer survival were LVEF > 35%, ≤2 prior systemic therapies, ≤2 metastatic sites, and normal lactate dehydrogenase and albumin levels.

CONCLUSION

Echocardiography would improve patient selection for enrollment in phase I clinical trials. These data suggest that it is safe to treat patients with LVEF between 35% and 50%.

Toxicity of targeted therapy: Implications for response and impact of genetic polymorphisms

Targeted therapies have unique toxicity profiles. Common adverse events include rash, diarrhea, hypertension, hypothyroidism, proteinuria, depigmentation, and hepatotoxicity. Some of these toxicities are caused by on-target, mechanism-associated effects, which can be stratified as to whether or not the targets are relevant to response. Other toxicities are off-target and may be caused by the class of agent, e.g. antibody vs small molecule tyrosine kinase inhibitor, or by immune reactions or toxic metabolites. Both on- and off-target toxicities may be due to higher drug concentrations or altered end-organ sensitivity, which in turn can be a consequence of genetic polymorphisms controlling metabolism or tissue responsiveness. On-target toxicities are important to identify as some correlate with response and, hence, amelioration of these side effects is preferable to dose reduction or stopping drug. Toxicities secondary to relevant target impact may be recognized when distinct types of agents, such as antibodies and small molecule kinase inhibitors, with the same target have a similar side effect. For example, both bevacizumab and vascular endothelial growth factor receptor (VEGFR) kinase inhibitors cause hypertension; both epidermal growth factor receptor (EGFR) antibodies and kinase inhibitors cause rash; and these toxicities correlate with response. Herein we review common targeted agent-related toxicities, relevant genetic polymorphisms, and implications for response and patient management.

Chemotherapy and QT Prolongation: Overview With Clinical Perspective

OPINION STATEMENT

Cardiotoxic adverse events are of concern to physicians treating cancer patients; they are encountered with a variety of agents. Cardiac events may delay the approval of new drugs or impose burdensome monitoring requirements as either part of the pre-approval process or in the daily use of these agents. Among the cardiac issues are the development of QT prolongation and the fear of torsades de pointes (TdP), an unusual yet potentially fatal form of ventricular tachycardia associated with QT prolongation. Several risk factors, including electrolyte imbalance and polypharmacy with concomitant QT prolonging agents use can increase the risk of TdP in cancer patients; separating the individual contributions of the various triggers for TdP remains problematic. Understanding the individual risk of QT prolongation associated with particular chemotherapies can better differentiate between those shown to have higher risk vs. those with lower risk potential. Cardiac monitoring and electrocardiogram analysis require recognition of the common challenges with regard to the precise measurement of the QT interval such as the presence of U waves, intraventricular conduction delays, and heart rate correction. Rapid identification and treatment of QT prolongation and TdP is critical in mitigating the risk of sudden cardiac death in cancer patients. A multidisciplinary treatment approach among cardiologists and oncologists should be employed to help facilitate an appropriate balance between oncologic efficacy and adverse cardiac events.

Compliance in early-phase cancer clinical trials research

Regulations and ethical principles require that investigators seek consent and that patients participate in experimental studies only under circumstances that minimize the possibility of undue pressure and/or enticements. In recent years, there has been a rapid rise in the monitoring requirements of early-phase trials accompanied by an increasing emphasis on assuring "investigator" compliance with the protocol. It is actually, however, the patient who must comply with the requirements of the study. If there is divergence from the protocol, investigators may be reported to regulatory bodies or agencies. Whereas the investigative community is expected to be vigilant about ensuring that patients participate in studies voluntarily and that their consent is procured without duress, it is also required to guarantee that complex protocols, which entail multiple procedures, be followed exactly by participants who suffer from the complications of advanced cancer. We explore the issue of compliance in a research environment in which investigators are subject to disciplinary action if they fail to ensure that patients adhere precisely to the intense monitoring mandates of a clinical trial.