Prospective evaluation of doxorubicin-induced cardiomyopathy resulting from postsurgical adjuvant treatment of patients with soft tissue sarcomas

Real-life incidence of cardiotoxicity and associated risk factors in sarcoma patients receiving doxorubicin

BACKGROUND

Anthracycline induced cardiotoxicity is well recognized but only few data exist in sarcoma patients. This study retrospectively aimed to analyze sequential Cadmium Zinc Telluride (CZT)-multigated equilibrium radionuclide angiography (ERNA) for monitoring left ventricular ejection fraction (LVEF) and to assess the real-life incidence of cardiotoxicity in sarcoma patients receiving doxorubicin based chemotherapy.

MATERIALS AND METHODS

A retrospective analysis was performed on all sarcoma patients referred to Herlev University Hospital between 2012 and 2015. Cardiotoxicity was defined as a decline in LVEF of > 10% percentage point to a LVEF < 50% as compared to baseline. Early cardiotoxicity was defined as < 1 year and late cardiotoxicity as ≥ 1 year. Recovery of cardiotoxicity was defined as a LVEF ≥ 50%.

RESULTS

A total of 149 patients were referred, 75 (50%) sarcoma patients were included. The main reason for exclusion was that only one CZT-ERNA had been performed in 50 (68%) of the patients. Twenty-three (31%) of the patients experienced cardiotoxicity, 11 (48%) were female, mean age was 56.9 years. Early cardiotoxicity was observed in 16 (70%) of the patients and 11 (48%) experienced clinical symptoms of cardiotoxicity at diagnosis. Recovery of LVEF was seen in 12 (55%) of the patients and persistent recovery in 10 (45%). The diastolic blood pressure at baseline was positively and significantly associated with a higher risk of developing cardiotoxicity (Relative Risk (RR): 1.039 (95% CI= 1.001 - 1.079; p = 0.042)). The median survival was 1.4 years (range 0.5 - 2.2 years) for patients with metastatic disease versus 3.9 years (range 1.5 - 6.4 years) (p = 0.009) for localized disease at baseline.

CONCLUSION

Cardiotoxicity is a relative frequent complication in sarcoma patients treated with doxorubicin based chemotherapy and the diastolic blood pressure at baseline was significantly associated with a higher risk of developing cardiotoxicity.

Mechanism of doxorubicin cardiotoxicity evaluated by integrating multiple molecular effects into a biophysical model

BACKGROUND AND PURPOSE

Doxorubicin (DOX) is an effective cancer therapeutic agent but causes therapy-limiting cardiotoxicity. The effects of DOX and its metabolite doxorubicinol (DOXL) on individual channels have been well characterized in isolation. However, it is unknown how the action and interaction of affected channels combine to generate the phenotypic cardiotoxic outcome. We sought to develop an in silico model that links drug effects on channels to action potential duration (APD) and intracellular Ca²⁺ concentration in order to address this gap in knowledge.

EXPERIMENTAL APPROACH

We first propose two methods to obtain, from published values, consensus drug effects on the currents of individual channels, transporters and pumps. Separately, we obtained equivalent values for APD and Ca²⁺ concentration (the readouts used as surrogates for cardiotoxicity). Once derived, the consensus effects on the currents were incorporated into established biophysical models of the cardiac myocyte and were refined adjusting the sarcoplasmic reticulum Ca²⁺ leak current (I_Leak ) until the consensus effects on APD and Ca²⁺ dynamics were replicated. Using factorial analysis, we then quantified the relative contribution of each channel to DOX and DOXL cardiotoxicity.

KEY RESULTS

The factorial analysis identified the rapid delayed rectifying K⁺ current, the L-type Ca²⁺ current and the sarcoplasmic reticulum I_Leak as the targets primarily responsible for the cardiotoxic effects on APD and Ca²⁺ dynamics.

CONCLUSIONS AND IMPLICATIONS

This study provides insight into the mechanisms of DOX-induced cardiotoxicity and a framework for the development of future diagnostic and therapeutic strategies.

Cardiovascular mortality trends in non-Hodgkin's lymphoma: a population-based cohort study

BACKGROUND

Non-Hodgkin's lymphoma (NHL) survivors are at a higher risk of cardiovascular diseases (CVDs).

METHODS

A population-based study was conducted to investigate the cardiovascular mortality trends to identify NHL survivors at the highest risk.

RESULTS

The CVDs mortality was the second most common cause of death (13.07%) after NHL. There were more patients ≥ 60 years old in the cardiovascular group (87.2%), P < 0.001. Patients who died from CVDs had the best survival while patients who died from NHL had a significantly lower mean survival. The overall survival rate was 92.4%. Consistently, older age, unmarried, male patients, not recently diagnosed with NHL and not receiving radiation and/or surgery were associated with a worse survival across all models. The black race and stage IV only had a worse cardiovascular specific survival (CVSS).

CONCLUSIONS

Although the CVSS improved over time, the mortality from the CVDs is still the second most common cause of death after NHL. Older age, not married, black, male patients, not recently diagnosed with NHL, with an advanced stage and not receiving radiation and/or surgery were associated with a worse survival. Risk factor modification along with CVDs screening should be intensified in NHL patients with these mortality predictors.

Monitoring tumor response with radiolabeled nucleoside analogs in a hepatoma-bearing mouse model early after doxisome(®) treatment

PURPOSE

This study aims to demonstrate that 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) positron emission tomography (PET) is a promising modality for noninvasively monitoring the therapeutic efficacy of Doxisome(®) in a subcutaneous hepatoma mouse model.

PROCEDURES

Male BALB/c nu/nu mice were inoculated with HepG2 hepatoma xenograft in the right flank. Doxisome(®) (5 mg/kg, three times a week for 2 weeks) was intravenously administrated for treatment. (18)F-FLT-microPET, biodistribution studies, and immunohistochemistry of Ki-67 were performed.

RESULTS

A significant difference (p < 0.05) in tumor volume was observed on day 5 between treated and control groups. The tumor-to-muscle ratio derived from (18)F-FLT-PET and (123)I-ICdR-microSPECT images of Doxisome(®)-treated mice dropped from 12.55 ± 0.76 to 3.81 ± 0.31 and from 2.48 ± 0.42 to 1.59 ± 0.08 after a three-dose treatment, respectively, while that of the control group remained steady. The retarded proliferation rate of treated xenograft was confirmed by Ki-67 immunohistochemistry staining.

CONCLUSIONS

This study clearly demonstrated that Doxisome(®) is an effective anti-cancer drug against the growth of HepG2 hepatoma and that (18)F-FLT-PET could provide early information of tumor response during treatment.

Doxorubicin-induced cardiotoxicity in adult Indian patients on chemotherapy

Background:

Doxorubicin-induced cardiotoxicity is widely known to occur at cumulative doses exceeding 450 mg/m². However, very few studies have reported incidence of cardiac dysfunction in patients on chemotherapy with lower cumulative doses. To the best of our knowledge, there is no study carried out so far that has reported the incidence of cardiac dysfunction in adult Indian patients receiving doxorubicin. This study was undertaken to determine the incidence of doxorubicin-induced cardiotoxicity by serial resting echocardiography in patients on chemotherapy and identify risk factors associated with cardiotoxicity.

Materials and Methods:

Patients that were started on doxorubicin-based chemotherapy in the period from January 2000 to June 2001 and had completed at least 300 mg/m² cumulative dose were taken in the study. Electrocardiography, chest X-ray and echocardiography were done at baseline, at 300 mg/m² and at 450 mg/m² cumulative doses of doxorubicin. All patients were evaluated for the presence of the following risk factors: Age>70 years, female sex, preexisting cardiac disease, hypertension, chest wall irradiation, body mass index (BMI)<20 kg/m² , Karnofsky performance status, combination chemotherapy with cyclophosphamide and presence of liver disease. Subclinical cardiac dysfunction was defined as ejection fraction fall greater than 10% on follow-up echocardiography.

Results:

Thirty patients satisfied the criterion for being considered for evaluation. One (3%) patient developed congestive cardiac failure, while 8 (27%) patients developed subclinical cardiac dysfunction. Concomitant use of cyclophosphamide significantly increased the risk of cardiac dysfunction (P = 0.048), while low BMI (<20 kg/m²) and preexisting cardiac disease showed a trend towards increased risk of cardiac dysfunction (P = 0.07 for both).

Conclusion:

Twenty-seven percent of the patients developed subclinical cardiac dysfunction in the cumulative dose range of 300-450 mg/m² . This entails regular monitoring for cardiac dysfunction by echocardiography during treatment.

Chemotherapy induced cardiomyopathy: pathogenesis, monitoring and management

The survival rate of cancer patients has greatly increased over the last 20 years. However, to achieve this result, a considerable price has been paid in terms of the side effects associated with the intensive anticancer treatment. The most common adverse effect is cardiotoxicity which may compromise the clinical effectiveness of chemotherapy, affecting the patient's survival and quality of life independently of the oncological prognosis. There are 2 types of cardiac toxicities, type I which is more serious and result in permanent damage to the myocardium and type II which is usually reversible. Chemotherapies varies in their incidence of inducing cardiomyopathy, and the onset which may occur acutely (during or shortly after treatment), sub-acutely (within days or weeks after completion of chemotherapy) or chronically (weeks to months after drug administration). Cardiac events associated with chemotherapy may consist of mild blood pressure changes, thrombosis, Electrocardiographic (ECG) changes, arrhythmias, myocarditis, pericarditis, myocardial infarction, cardiomyopathy, cardiac failure (left ventricular failure), and congestive heart failure (CHF). The risk for such effects depends upon: cumulative dose, rate of drug administration, mediastinal radiation, advanced age, younger age, female gender, pre-existing heart disease and hypertension. Serial measurements of LVEF and fractional shortening are the most common indices monitored to assess left ventricular systolic function and cardiotoxicity. This can be achieved by 2-dimensional, M-mode and color Doppler echocardiographic examination; also Cardiac troponins as a biological marker for myocardial damage can be used for monitoring in patients received anthracyclines. Angiotensin-converting enzyme (ACE) inhibitors (ACEIs) have been shown to slow the progression of left ventricular dysfunction in several different clinical settings, including anthracycline-induced cardiomyopathy. Carvedilol and probably with anti-oxidants like Probucol and vitamin E benefits also.

Musculoskeletal desmoid tumors

Desmoid tumors are benign tumors that exhibit varying degrees of local aggressiveness and diverse growth patterns. Magnetic resonance imaging remains the modality of choice for assessment of the nature and size of the soft-tissue lesion and involvement of surrounding structures. Treatment strategies include surgery, chemotherapy, hormonal therapy, and radiation therapy, either individually or in combination. Despite the benign nature of these tumors, multidisciplinary care is needed to provide combined treatment options. Chemotherapy in low doses is an excellent first-round treatment in any patient in whom contemplated local treatment may produce local morbidity and adjacent tissue injury.

Cardioprotective effect of dexrazoxane in patients with breast cancer treated with anthracyclines in adjuvant setting: a 10-year single institution experience

BACKGROUND AND OBJECTIVE

Anthracyclines are highly effective and widely used cytotoxic agents, but their application is often limited by cumulative dose-dependent cardiotoxicity. Dexrazoxane has been shown in several clinical trials to prevent the development of this serious toxicity. The aim of our study was to analyze the incidence of cardiac dysfunction over a 10-year period in patients with breast cancer who were treated with anthracycline-based regimens with addition of dexrazoxane, mainly in an adjuvant setting.

METHODS

We conducted a retrospective analysis on a population of women with breast cancer treated at our institution between January 1993 and October 2003. We reviewed patients' medical records and data on patient characteristics, treatment history, and adverse events that were collected, starting from the time of first visit before starting therapy, with the use of software created and designed for clinical records management in our institution (1999 OK-DH). Patients underwent an ECG assessment prior to starting chemotherapy, and were clinically monitored for cardiac failure. Those who developed signs and symptoms suggestive of cardiac dysfunction underwent further ECG. If clinical findings indicated, echocardiography and further cardiologic investigations were performed. The main outcome measure was the development of signs and symptoms indicative of congestive heart failure (CHF).

RESULTS

A total of 318 female patients were treated with an anthracycline (doxorubicin or epirubicin)-based combination chemotherapy regimen during this time, in most cases in the adjuvant setting (n = 285). Most patients (n = 302) had early-stage disease and only 16 women presented with metastatic disease with good life expectancy (at least 1 year). All patients received dexrazoxane 1000 mg/m(2) intravenously prior to anthracycline administration during each chemotherapy cycle. The median follow-up duration was 35 months. During this time, five patients (1.57%) developed signs and symptoms of CHF. No patient at our institution died of heart failure during the period analyzed. Dexrazoxane was well tolerated, with no reports of adverse events associated with this drug.

CONCLUSIONS

The reported incidence of cardiotoxicity in this study represents a marked reduction compared with historical data for patients receiving anthracycline-based chemotherapy without dexrazoxane. Dexrazoxane appears to have a cardioprotective effect in women with early-stage or advanced breast cancer treated with anthracycline-based combination chemotherapy, mainly as an adjuvant treatment. Prospective, randomized, controlled clinical trials in adjuvant setting should be performed to confirm these results.

New insights into doxorubicin-induced cardiotoxicity: the critical role of cellular energetics

Cardiotoxic side-effects represent a serious complication of anticancer therapy with anthracyclines, in particular with doxorubicin (DXR) being the leading drug of the group. Different hypotheses, accentuating various mechanisms and/or targets, have been proposed to explain DXR-induced cardiotoxicity. This review focuses on the myocardial energetic network as a target of DXR toxic action in heart and highlights the recent advances in understanding its role in development of the DXR related cardiac dysfunction. We present a survey of DXR-induced defects in different steps of cardiac energy metabolism, including reduction of oxidative capacity of mitochondria, changes in the profile of energy substrate utilization, disturbance of energy transfer between sites of energy production and consumption, as well as defects in energy signaling. Considering the wide spectrum and diversity of the changes reported, we attempt to integrate these facts into a common framework and to discuss important functional and temporal relationships between DXR-induced events and the possible underlying molecular mechanisms.

Cardioprotective effect of dexrazoxane during treatment with doxorubicin: a study using low-dose dobutamine stress echocardiography

AIM

To assess the late cardioprotective effect of dexrazoxane associated with doxorubicin during treatment of osteosarcoma by means of low-dose dobutamine stress echocardiography (LDDSE) in non-relapsed asymptomatic children and teenagers.

PATIENTS AND METHODS

The study population included 58 patients with osteosarcoma divided in three groups, with equivalent age range, gender proportion and body surface area. Group I (21 patients, 14 males, 15 +/- 4 years) was analyzed before chemotherapy and considered the control group; Group II (19 patients, 11 males, 19.7 +/- 4 years) was treated with 348.4 +/- 18 mg/m2 of doxorubicin only and Group III (18 patients, 14 male, 16.8 +/- 5 years) treated with 396.5 +/- 55 mg/m2 of doxorubicin with dexrazoxane in the ratio 10:1. The patients were submitted to LDDSE (maximal dose 5 microg/kg/min). No major side effects were observed. Heart rate, blood pressure, left ventricular diameters, end systolic wall stress (ESWS), and other diastolic and systolic function indexes were assessed at rest conditions and during LDDSE and compared between the three groups.

RESULTS

Group III received a doxorubicin dose significantly greater than Group II (P = 0.001). During LDDSE there were no significant changes in the diastolic function indexes in any of the groups, but there was a significant increase of systolic indexes and a decrease of ESWS in Group III compared to group II. There was no significant difference of any systolic functional parameters between Group I and III. Considering the ejection fraction (EF) at rest or at LDDSE, 13 patients (69.4%) in Group II and 5 patients (27.7%) in Group III were considered to have systolic dysfunction. (P = 0.02).

CONCLUSION

Myocardial response to LDDSE in patients treated with doxorubicin and dexrazoxane was similar to patients without chemotherapy and better than those treated with doxorubicin only, suggesting less cardiotoxicity.

Cardiotoxicity of cancer chemotherapy: implications for children

Many children and adolescents with cancer receive chemotherapeutic agents that are cardiotoxic. Thus, while survival rates in this population have improved for some cancers, many survivors may experience acute or chronic cardiovascular complications that can impair their quality of life years after treatment. In addition, cardiac complications of treatment lead to reductions in dose and duration of chemotherapy regimens, potentially compromising clinical efficacy. Anthracyclines are well known for their cardiotoxicity, and alkylating agents, such as cyclophosphamide, ifosfamide, cisplatin, busulfan, and mitomycin, have also been associated with cardiotoxicity. Other agents with cardiac effects include vinca alkaloids, fluorouracil, cytarabine, amsacrine, and asparaginase and the newer agents, paclitaxel, trastuzumab, etoposide, and teniposide. The heart is relatively vulnerable to oxidative injuries from oxygen radicals generated by chemotherapy. The cardiac effects of these drugs include asymptomatic electrocardiographic abnormalities, blood pressure changes, arrhythmias, myocarditis, pericarditis, cardiac tamponade, acute myocardial infarction, cardiac failure, shock, and long-term cardiomyopathy. These effects may occur during or immediately after treatment or may not be apparent until months or years after treatment. Mild myocardiocyte injury from chemotherapy may be of more concern in children than in adults because of the need for subsequent cardiac growth to match somatic growth and because survival is longer in children. Primary prevention is therefore important. Patients should be educated about the cardiotoxic risks of treatment and the need for long-term cardiac monitoring before chemotherapy is begun. Cardiotoxicity may be prevented by screening for risk factors, monitoring for signs and symptoms during chemotherapy, and continuing follow-up that may include electrocardiographic and echocardiographic studies, angiography, and measurements of biochemical markers of myocardial injury. Secondary prevention should aim to minimize progression of left ventricular dysfunction to overt heart failure. Approaches include altering the dose, schedule, or approach to drug delivery; using analogs or new formulations with fewer or milder cardiotoxic effects; using cardioprotectants and agents that reduce oxidative stress during chemotherapy; correcting for metabolic derangements caused by chemotherapy that can potentiate the cardiotoxic effects of the drug; and cardiac monitoring during and after cancer therapy. Avoiding additional cardiotoxic regimens is also important in managing these patients. Treating the adverse cardiac effects of chemotherapy will usually be dependent on symptoms or will depend on the anticipated cardiovascular effects of each regimen. Treatments include diuresis, afterload reduction, beta-adrenoceptor antagonists, and improving myocardial contractility.

Pediatric heart transplantation for anthracycline cardiomyopathy: Cancer recurrence is rare

BACKGROUND

Although anthracycline therapy is invaluable for treating neoplastic disorders, morbidity includes severe cardiomyopathy that leads to heart transplantation. This multicenter study describes the course of children who experienced anthracycline cardiomyopathy (ACM) and who subsequently required heart transplantation.

METHODS

We reviewed transplant databases/registries at 4 pediatric heart transplant centers to identify children with ACM who were listed for heart transplantation. We reviewed medical records to determine cancer therapy, clinical course, and outcome.

RESULTS

Eighteen patients were listed, and 17 underwent transplantation. Mean age at cancer diagnosis was 6.0 years (SD, 3.7). The mean anthracycline dose was 361 mg/m2 (SD, 110). The median time from cancer diagnosis to listing for heart transplantation was 9.2 years (range, 0.4-15.2 years). Six transplantations were performed in patients who had disease-free intervals of <5 years. Two patients were lost to follow-up, and 8 are alive at 4.9 years (SD, 2.0; range, 1.3-7.4 years) after transplantation. Seven patients died at 4.7 years (SD, 2.0; range, 1.2-7.1 years) after transplantation. One patient had recurrent cancer. One-, 2- and 5-year survivals were 100%, 92%, and 60%, respectively.

CONCLUSIONS

Cardiomyopathy that progresses to the need for heart transplantation occurs in patients receiving a wide range of cumulative anthracycline doses. The time from chemotherapy to ACM varies. Outcomes after transplantation are acceptable, and cancer recurrence is rare. Reconsideration of the 5-year disease-free wait period is warranted.

Adriamycin and cis-platinum as first-line treatment in unresectable locally advanced or metastatic adult soft-tissue sarcomas

Standard chemotherapy in advanced adult soft-tissue sarcomas (STS) has not yet been established. We evaluated the efficacy and toxicity of the combination of adriamycin (ADR) and cis-platinum (CDDP) as first-line treatment in nonoperable locally advanced or metastatic adult STS. Thirty patients were treated with CDDP 100 mg/m2 on day 1 and ADR 75 mg/m2 equally divided on days 1 to 3, every 3 weeks for 6 cycles. Patients were evaluated for response, toxicity, and survival, while resectability of residual disease was also assessed after the third cycle and the end of chemotherapy. No complete response was observed. Five patients (16.7%, 95% CI: 2.5%-31%) achieved partial response, 16 patients (53.3%, 95% CI: 34%-72%) had stable disease and 9 patients (30%, 95% CI: 13%-47%) had progressive disease. The overall median survival was 11.5 months (range, 4-96 months), and the median time to disease progression was 6 months (range, 0-96 months). Furthermore, two patients with PR and six patients with stable disease underwent further surgery followed by radiotherapy in four of them. At present, 5 patients remain free of relapse for 96, 90, 72, 60, and 48 months, respectively. Treatment-related toxicity was acceptable, with moderate myelosuppression and alopecia as the main adverse events. The ADR/CDDP regimen was well tolerated, but it did not achieve a high response rate. However, patients with resectable disease after chemotherapy achieved long-term survival. Further studies are needed to evaluate the role of combined-modality treatments in the management of patients with advanced STS.

Long-term cardiac sequelae in operable breast cancer patients given adjuvant chemotherapy with or without doxorubicin and breast irradiation

PURPOSE

To investigate long-term cardiac sequelae associated with anthracycline use in adjuvant chemotherapy of patients with early breast cancer.

PATIENTS AND METHODS

All 1,000 patients from three prospective trials of adjuvant chemotherapy containing doxorubicin (n = 637, median total dose of 294 mg/m(2)) or not containing the anthracycline (cyclophosphamide, methotrexate, and fluorouracil [CMF] regimen alone, n = 363) were analyzed for the relative incidence of congestive heart failure (CHF) and myocardial infarction (MI) during 14 years of follow-up. The 462 women continuously free of disease as of February 1996 were recalled, and 355 consented to undergo evaluation including 12-lead ECG and cardiac ultrasound with determination of left ventricular ejection fraction (LVEF) to assess the relative incidence of abnormalities in long-term survivors.

RESULTS

Among the 1,000 patients, there were six cases of CHF and three cases of MI. Cumulative cardiac mortality accounted for 0.4% (doxorubicin-treated = 0.6%; CMF-treated = 0). Eighteen (5%) of the 355 patients undergoing cardiac evaluation after median 11 years of follow-up presented systolic dysfunction as defined by pathologic (< 50%, n = 8) or borderline (50% to 55%, n = 10) LVEF. Systolic dysfunction was higher in doxorubicin-treated (15 of 192; 8%) than in CMF-treated patients (three of 150; 2%). Breast irradiation had a significant impact on the occurrence of early CHF (four of 116; 3%), but not on systolic dysfunctions.

CONCLUSION

At longer than 10 years of follow-up, the use of doxorubicin at a total dose commonly applied in regimens of adjuvant chemotherapy does not lead to cardiac clinical sequelae that counter-balance the benefit of treatment in patients with operable breast cancer who may be cured of their disease.

High incidence of adriamycin cardiotoxicity in children even at low cumulative doses: role of radionuclide cardiac angiography

BACKGROUND/PURPOSE

Adriamycin (doxorubicin), a chemotherapeutic agent commonly used in the treatment of pediatric solid tumors, is known to have a dose-related cardiotoxicity, which is reported to be more common in children. The clinical manifestation of this is congestive cardiac failure (CHF), and this is fatal in 50% of the cases. Various strategies, including prospective multiple gated acquisition (MUGA) scan for early detection of the onset of cardiac damage has been recommended to decrease this fatality caused by cardiotoxicity.

METHODS

All children receiving Adriamycin for solid tumors, registered at our pediatric solid tumor clinic from January 1998 through June 1999, were included in the study. Cardiotoxicity was evaluated by using electrocardiogram (ECG)-gated radionuclide cardiac angiography (MUGA scan).

RESULTS

MUGA scans were performed on 55 patients in the above-mentioned period of 18 months. Twenty-three patients had only 1 baseline MUGA scan done, 12 of these are awaiting further studies at appropriate time and 11 are either dead or lost to follow-up. Of the remaining 32 patients, 13 have shown evidence of cardiotoxicity on MUGA scan done at a cumulative dose of 180 to 200 mg/m(2), in the form of decrease in left ventricular ejection fraction (LVEF) or abnormality in myocardial movements. Three of these 13 patients had clinical evidence of CHF. In 10 patients, timely discontinuation of Adriamycin, based on the MUGA report, probably has helped avoid the development of CHF.

CONCLUSION

Routine monitoring of all children receiving Adriamycin is required to avoid the mortality and morbidity of Adriamycin-related cardiotoxicity, which may develop at relatively low cumulative doses also.

Cardiotoxicity of chemotherapeutic agents: incidence, treatment and prevention

Cytostatic antibiotics of the anthracycline class are the best known of the chemotherapeutic agents that cause cardiotoxicity. Alkylating agents such as cyclophosphamide, ifosfamide, cisplatin, carmustine, busulfan, chlormethine and mitomycin have also been associated with cardiotoxicity. Other agents that may induce a cardiac event include paclitaxel, etoposide, teniposide, the vinca alkaloids, fluorouracil, cytarabine, amsacrine, cladribine, asparaginase, tretinoin and pentostatin. Cardiotoxicity is rare with some agents, but may occur in >20% of patients treated with doxorubicin, daunorubicin or fluorouracil. Cardiac events may include mild blood pressure changes, thrombosis, electrocardiographic changes, arrhythmias, myocarditis, pericarditis, myocardial infarction, cardiomyopathy, cardiac failure (left ventricular failure) and congestive heart failure. These may occur during or shortly after treatment, within days or weeks after treatment, or may not be apparent until months, and sometimes years, after completion of chemotherapy. A number of risk factors may predispose a patient to cardiotoxicity. These are: cumulative dose (anthracyclines, mitomycin); total dose administered during a day or a course (cyclophosphamide, ifosfamide, carmustine, fluorouracil, cytarabine); rate of administration (anthracyclines, fluorouracil); schedule of administration (anthracyclines); mediastinal radiation; age; female gender; concurrent administration of cardiotoxic agents; prior anthracycline chemotherapy; history of or pre-existing cardiovascular disorders; and electrolyte imbalances such as hypokalaemia and hypomagnesaemia. The potential for cardiotoxicity should be recognised before therapy is initiated. Patients should be screened for risk factors, and an attempt to modify them should be made. Monitoring for cardiac events and their treatment will usually depend on the signs and symptoms anticipated and exhibited. Patients may be asymptomatic, with the only manifestation being electrocardiographic changes. Continuous cardiac monitoring, baseline and regular electrocardiographic and echocardiographic studies, radionuclide angiography and measurement of serum electrolytes and cardiac enzymes may be considered in patients with risk factors or those with a history of cardiotoxicity. Treatment of most cardiac events induced by chemotherapy is symptomatic. Agents that can be used prophylactically are few, although dexrazoxane, a cardioprotective agent specific for anthracycline chemotherapy, has been approved by the US Food and Drug Administration. Cardiotoxicity can be prevented by screening and modifying risk factors, aggressively monitoring for signs and symptoms as chemotherapy is administered, and continuing follow-up after completion of a course or the entire treatment. Prompt measures such as discontinuation or modification of chemotherapy or use of appropriate drug therapy should be initiated on the basis of changes in monitoring parameters before the patient exhibits signs and symptoms of cardiotoxicity.

Anthracycline-induced cardiomyopathy

Anthracycline cardiomyopathy is less frequently encountered nowadays, due to the well-recognised dose limitations and cardiac monitoring protocols used by chemotherapy centres. However, it is a condition that will persist due to the sensitivity of some patients to these drugs and the necessity for large doses to be used for certain individuals. We have demonstrated the benefit of angiotensin-converting enzyme inhibitor therapy and would consider introducing these compounds at the earliest opportunity. The use of probucol and vitamins as antioxidants capable of preventing the onset of cardiomyopathy in humans appears to require further investigation but may significantly reduce the incidence of this condition in the future.

Diagnosis and treatment of soft tissue tumors

In the management of soft-tissue tumors, accurate diagnosis, using a combination of clinical, radiographic, and histological data, is critical in optimizing outcome. Radiographic diagnoses can be useful, but they cannot accurately predict histology or whether a lesion is benign or malignant. Therefore, all soft lumps that persist or grow should be biopsied if possible. Fine-needle aspiration biopsy is useful in differentiating benign from malignant lesions. Core-needle biopsies can yield a histological diagnosis when the sample is sufficiently large. When open biopsy is required, the skin incision must be carefully placed so that the biopsy site can be completely excised if the lesion is subsequently found to be malignant. Excisional biopsy should be used only for small lesions or when the surgeon is confident that the lesion is benign. If, following excision, the lesion is found to be malignant or desmoid, additional surgery with an adequate excision margin should be performed. In the resection of high-grade sarcomas treated by surgery alone or resistant to preoperative adjuvant therapies, a "curative (wide) margin" must be achieved. We occasionally use preoperative radiation with or without hyperthermia for malignant lesions in the vicinity of neurovascular structures where adequate surgical margins are unlikely to be achieved. The use of chemotherapy is justified only in small-cell sarcomas in which metastasis occurs frequently and chemotherapy is known to be effective. For high-grade spindle-cell or pleomorphic sarcomas, the value of adjuvant chemotherapy remains controversial and needs investigation.

Cancer chemotherapy in the elderly

As the geriatric population is growing, it is increasingly important to be familiar with chemotherapy for the elderly. Age-related changes in pharmacokinetics are documented for doxorubicin, etoposide, ifosfamide, daunorubicin, mitomycin, cisplatin and methotrexate. The hematological toxicity of most standard-dose chemotherapy is not affected by age in patients with normal organic functions and good performance status, although increased toxicity with aging is suggested in the use of actinomycin-D, etoposide, vinblastin, methotrexate, methyl-CCNU, doxorubicin and mitomycin, and in dose-intensive chemotherapy. Among non-hematological toxicities, only doxorubicin-induced cardiomyopathy and bleomycin-induced pulmonary toxicity are demonstrated to be accelerated in the elderly. There is no evidence that advanced age decreases the efficacy of chemotherapy for tumors, except for Hodgkin's disease and acute leukemia. These results suggest that advanced chronological age alone is not always associated with severe toxicity and poor prognosis, and that many elderly patients with cancer will benefit from chemotherapy. To answer questions regarding the optimal chemotherapy regimen, dose and intensity in this population, the influence of age should be analyzed in a multivariate approach in future studies.

A randomized comparison of the efficacy and toxicity of epirubicin and doxorubicin in the treatment of patients with non-Hodgkin's lymphoma

BACKGROUND

Combination chemotherapy consisting of methotrexate, doxorubicin, cyclophosphamide, vincristine, prednisolone, and bleomycin (MACOP-B) has been frequently used for the treatment of non-Hodgkin's lymphoma. This randomized study was undertaken to assess the efficacy and toxicity of this regimen when either doxorubicin or epirubicin was used as the anthracycline drug.

METHODS

Between April 1989 and December 1993, 211 previously untreated patients with intermediate grade and high grade non-Hodgkin's lymphoma were randomized to receive either doxorubicin (n=106) or epirubicin (n=105) with the MACOP-B regimen. These patients were followed through December 1996. Numerous clinical features predictive of response and survival were analyzed. Cardiac and noncardiac toxicity in the two treatment arms were compared.

RESULTS

The median age of the patients was 48 years. Complete remission was experienced by 122 patients (58.3%); 62 patients (58.5%) achieved complete remission in the doxorubicin arm and 60 (58.1%) in the epirubicin arm. Response rates, time to treatment failure, relapse data, and overall survival were comparable between the two arms. Morbidity due to mucositis, vomiting, peripheral neuropathy, and cardiotoxicity were also comparable. The overall mortality was 10%. Mortality due to neutropenic sepsis was considerably higher among patients who received epirubicin (10 patients) than among those who received doxorubicin (5 patients). Cardiac evaluation revealed no difference in toxicity between the two arms.

CONCLUSIONS

Epirubicin was as effective as doxorubicin in terms of patients' responses to therapy. There was no difference in cardiotoxicity between the two treatment arms. However, in this study, the mortality due to neutropenic sepsis was significantly higher among patients treated with epirubicin.

The role of radionuclide angiocardiography in the treatment of patients receiving doxorubicin-based chemotherapy: a reassessment

We attempted to evaluate the role of radionuclide angiography in the routine treatment of patients receiving doxorubicin-based therapy in a university hospital setting. We identified 222 cancer patients treated with doxorubicin or who underwent radionuclide angiography with the intent to receive doxorubicin at the University of Iowa in 1989. We examined the cumulative doses of doxorubicin, results of radionuclide angiograms, cardiac risk factors, and clinical outcomes and survival of patients. Of 222 patients, 168 (76%) underwent at least one radionuclide angiogram and received doxorubicin. Only a baseline study was performed in 136 (81%) of these 168 patients. Only 32 underwent follow-up study during therapy; six patients discontinued therapy for an 11-21% decrease in left ventricular function. The mean dose of doxorubicin received was 211 mg/m2, and 193 patients (96%) received a cumulative dose <450 mg/m2. Only two patients (1%) had heart failure. A questionnaire sent to medical oncologists in Iowa showed that use of radionuclide angiography in our institution reflected practice throughout the state. The majority of patients in our population who underwent radionuclide angiography had a single baseline study, which provides little clinically useful information. The majority of patients receiving doxorubicin as currently employed can be safely treated without radionuclide angiography.

The effect of aging on the utilization of chemotherapy for metastatic breast cancer: a population-based study

Older women (i.e., > or = 65 years of age) receive less adjuvant chemotherapy than younger women, in part because chemotherapy has been less effective in postmenopausal than premenopausal women in clinical trials. Metastatic breast cancer, however, does not respond differently to chemotherapy by age. Therefore, to evaluate further the effect of age on chemotherapy utilization, we conducted a population-based study of the treatment of metastatic breast cancer. Patients (n = 132) were identified by cross-tabulating death certificates from 1984 to 1991 with breast cancer cases in the Washington County Cancer Registry. Treatment information was obtained from the Tumor Registry of the Washington Country Hospital and Hospital medical records. Forty patients (74%) < 65 years old received chemotherapy compared to 11 (42%) 65-74 and 6 (12%) > or = 75 (p < 0.0001). Adjusting for other medical conditions and whether or not the patient saw a medical oncologist, there was still a significant effect of age in patients > or = 75 (p < 0.001) and a trend (p = 0.17) for patients 65-74. The different patterns of chemotherapy utilization were not associated with survival differences. Radiation therapy was also utilized significantly less frequently in older than younger patients, but the age effect was not as pronounced as with chemotherapy. There was no age effect on the utilization of hormonal therapy. Less frequent utilization of chemotherapy in older patients is probably caused by a combination of patient and physician factors and may result in less effective palliation for older patients.

Late cardiotoxicity after treatment for a malignant bone tumor

Cardiac function was assessed in long-term survivors of malignant bone tumors who were treated according to Rosen's T5 or T10 protocol, both including doxorubicin. Thirty-one patients, age 10-45 years (median age 17.8 years) were evaluated 2.3-14.1 years (median 8.9 years) following completion of treatment. Cumulative doses of doxorubicin were 225-550 mg/m2 (median dose 360). The evaluation consisted of a history, physical examination, electrocardiogram (ECG), signal averaged ECG, 24-hour ambulatory ECG, echocardiography and radionuclide angiography. Eighteen of 31 (58%) patients showed cardiac toxicity, defined as having one or more of the following abnormalities: late potentials, complex ventricular arrhythmias, left ventricular dilation, decreased shortening fraction, or decreased ejection fraction. The incidence of cardiac abnormalities increased with length of follow-up (P< or = .05). No correlation could be demonstrated between cumulative dose of doxorubicin and cardiac status, except for heart rate variability. When adjusted to body surface area, the left ventricular posterior wall thickness (LVPW index) was decreased in all patients. The incidence of doxorubicin-induced cardiotoxicity is high and increases with follow-up, irrespective of cumulative dose. Life-long cardiac follow-up in these patients is warranted. The results of our study suggest that heart rate variability and LVPW index could be sensitive indicators for cardiotoxicity.

[Pediatric aspects of anthracycline cardiotoxicity and practical implications for prevention]

Discovered during the sixties, anthracycline antibiotics are today widely used anti-cancer drugs. Their potentially fatal cardiac toxicity, which is related in part to the total cumulative dose, has been described since 1967. The aim of this paper is to describe their biological and clinical toxic effects on the heart, especially of children, and to propose prevention guidelines. The mechanisms of cardiac toxicity, with their destructive consequences on functional myocytes reserve, are shortly recalled. Acute, sub-acute and chronic clinical aspects of anthracycline's cardiomyopathy are the subject of a literature review. In Pediatric Oncology, the prolonged survival usually observed allows delayed congestive heart failure to occur by myocardial reserve insufficiency, as hemodynamic needs are quickly increasing, especially at the end of the somatic growth. Furthermore, the frequency of cardiac abnormalities is increasing with time after therapy, reaching about half of the explored patients after 15 years. The main known methods to prevent such a toxicity are reviewed. The parcimonious use of anthracyclines is already seen in children. Every method to decrease the maximal plasma concentration of the drug (weekly schedule or prolonged infusion) has to be considered. The active cardioprotectant agent such as ICRF-187, is in clinical development. Detection, prevention, and therapy of cardiac abnormalities, which are likely to precede delayed heart failure, still remains a difficult problem in these more and more numerous children to be cured of cancer.

Cardiac failure and dysrhythmias 6-19 years after anthracycline therapy: a series of 15 patients

The clinical course of late symptomatic anthracycline cardiomyopathy, and resultant changes of cardiac function, were described in 15 patients. They represented a subset of 300 patients who had cardiac evaluations to identify the prevalence of late cardiotoxicity more than 4 years after anthracycline therapy in these patients. The clinical course and all available cardiac evaluations including electrocardiography, continuous taped electrocardiography, echocardiography, radionuclide cardiac angiography, cardiac catheterization, and endomyocardial biopsy, of the 15 patients were reviewed. The patients had received 285-870 (median 540) mg/M2 of daunorubicin and/or doxorubicin 6-19 (median 12) years prior to the onset of late symptoms. Seven patients also had 2,100-4,000 cGy mediastinal radiotherapy. Five patients had required treatment for cardiac symptoms at the end of chemotherapy but 10 patients had no cardiac problems anteceding their late decompensation. Fractional shortening on echocardiogram at late decompensation was 8-20% (median 17%) and radionuclide left ventricular ejection fraction was 8-59% (median 38%). All were treated with digitalis and diuretics and 13/15 with afterload reduction, with at least transient improvement of symptoms. They were followed for 1-9 (median 3) years after late decompensation. One died of uncontrollable cardiac failure. Another underwent successful cardiac transplantation. Conduction abnormalities and dysrhythmias were present in 14/15 patients and 3 died suddenly. Two more had syncope, one requiring an automatic cardiac defibrillator. Endomyocardial biopsy or autopsy revealed hypertrophy and fibrosis in 10/10 patients. Our patients with early cardiac symptoms improved transiently but decompensated later and patients with no early symptoms developed cardiac symptoms more than 10 years after anthracycline therapy. Therefore, patients who have received anthracyclines should have continued cardiac evaluation.

Endomyocardial biopsy--technical aspects experience and current status. An Indian perspective

Our study ellucidates the utility of endomyocardial biopsy (EMB) in various cardiac-muscle disorders seen in a tropical country like India. The procedure has been successfully performed in 501 patients (572 procedures) at our centre from April 1985 to December 1992. This included 60 infants and children. The indications were dilated cardiomyopathy (DCM) in 214, non-specific aortoarteritis in 91, rheumatic heart disease in 75, restrictive cardiomyopathy in 45, constrictive pericarditis in 14 and miscellaneous in 62 patients. There was no mortality, however, one patient developed cardiac tamponade and another sustained ventricular tachycardia requiring cardioversion. There was transient atrial fibrillation in six patients and all these had acute rheumatic heart disease. Transient complete heart block occurred in six patients with underlying left-bundle branch-block. Histological examination of EMB revealed myocarditis in 34/214 (15.4%) patients in DCM group and helped in following up these cases on immunosuppressive treatment. In the presence of restrictive haemodynamics it could identify amyloidosis in four patients. It was also helpful in differentiating between endomyocardial fibrosis and chronic constrictive pericarditis. In patients with non-specific aorto-arteritis significant histological changes of inflammatory myocarditis were observed in patients especially in congestive heart failure. Furthermore, it was helpful in identifying the nature of cardiac tumour in one patient. Its utility has also been evaluated in disorders, including rheumatic heart disease, peripartum cardiomyopathy and systemic disorders like systemic lupus erythematosis. Even in the absence of cardiac-transplant programmes at national level we have found EMB to be a useful investigation in a tropical country like India.

Initial and reoperative pulmonary metastasectomy: indications, technique, and results

The ability to predict which patients will derive a survival benefit from pulmonary metastasectomy is limited. Most patients remain asymptomatic until the disease becomes advanced, and therefore computerized tomography (CT) of the chest has become the standard of care for follow-up of patients at risk for pulmonary metastases. The most important predictor of post-thoracotomy survival in patients at the National Cancer Institute with soft tissue, osteogenic, and pediatric sarcomas as well as melanoma and renal cell carcinoma has been the ability to render the patient disease-free. Tumor histology, disease-free interval, and possibly number of nodules are also determinants of survival. Median sternotomy is the preferred approach for initial and repeat metastasectomies and every effort should be made to preserve pulmonary parenchyma. Resection of pulmonary metastases has become an accepted therapeutic modality, but selection of surgical candidates, and operative planning needs to be individualized.

Doxorubicin-induced cardiotoxicosis. Clinical features in 32 dogs

Clinical cardiac abnormalities developed in 32 of 175 dogs that had various malignancies and were treated with doxorubicin: 31 dogs had electrocardiographic abnormalities including arrhythmias and nonspecific alterations in the R wave, ST segment, or QRS duration and 7 dogs had congestive heart failure. All seven dogs that had congestive heart failure died within 90 days. At necropsy, 13 of 32 affected dogs had noninflammatory myocardial degeneration, myocytolysis, vacuolation, and/or fibrosis and there was intramural coronary arteriosclerosis in all 13. Five dogs with lymphosarcoma were in complete clinical remission when they died of doxorubicin-induced cardiomyopathy, but the overall survival times of the lymphosarcoma subset was nevertheless longer than in previous studies. The clinical use of doxorubicin in the dog can cause cardiotoxicosis but the therapeutic benefit appears to outweigh risks in most dogs.

Etiology of sarcoplasmic reticulum calcium release channel lesions in doxorubicin-induced cardiomyopathy

Alterations in the native function of the ryanodine-sensitive Ca2+ release channel complex of sarcoplasmic reticulum (SR) isolated from rat cardiac ventricles during acute and chronic exposure to doxorubicin are examined. Compared to control SR, actively loaded SR from animals exposed to a single intravenous dose of doxorubicin exhibit faster rates of doxorubicin-induced Ca2+ release and the occupancy of [3H]ryanodine is significantly enhanced with subsequent exposure of SR membranes to doxorubicin in vitro. One week after acute exposure to doxorubicin in vitro, the EC50 for activation of the binding of [3H]ryanodine by Ca2+ is not significantly different from control SR. However, the persistence of doxorubicin-sensitized SR channels appears to be latent since repeated exposure to doxorubicin in vitro significantly enhances receptor occupancy in SR obtained from the treated rats compared to control SR. Ryanodine receptors from rats chronically exposed to doxorubicin consistently exhibit a higher sensitivity to activation Ca2+ which persists at least 4 weeks following the last injection of drug. Chronic exposure produces a concomitant reduction in the capacity of [3H]ryanodine binding sites. The marked decrease in receptor density observed with SR from doxorubicin-treated rats coincides with significant reduction in body weight, suggesting a possible influence of nutrition. However, sodium dodecyl sulfate polyacrylamide electrophoresis indicates no significant loss of the high molecular weight subunit of the ryanodine receptor, suggesting that loss of [3H]ryanodine-binding capacity may be the result of progressive and permanent channel desensitization. Consistent with desensitized receptors, membrane vesicles prepared from rats chronically exposed to doxorubicin take up significantly more Ca2+ and exhibit significantly reduced rates of doxorubicin or Ca2+/ryanodine induced Ca2+ release. The data demonstrates (i) doxorubicin inflicts cumulative SR channel lesions in vivo, (ii) a persistent sensitization of the SR channel to activation by Ca2+ and (iii) a significant and apparently irreversible reduction in the number of functional channel complexes.

Limb function following conservation treatment of adult soft tissue sarcoma

Quality of life and limb function were studied in 54 patients who were disease-free 2 or more years after limb-conserving treatment for soft tissue sarcoma of the leg or pelvic girdle. Tumours of the thigh predominated (25 patients) and the mean tumour size was 9.9 cm. 41 patients had been treated with a combination of surgery and radiotherapy (29 with conventional and 12 with high dose), 12 with surgery alone and one with irradiation and intra-arterial doxorubicin. Only 15 patients had a normal range of movement in all lower limb joints and only 12 had normal power in all muscle groups; tumours of the lower leg were particularly unfavourable in this respect. Gait was normal in 42 patients but 8 required a walking aid and 4 a joint support. 16 had detectable lymphoedema but only 2 needed to wear compression hosiery. 35 patients still experienced pain at some time but only 6 required analgesia. However, when assessed by questionnaire for locomotion, grooming and home/leisure/vocational activities, 37 patients (68%) reported excellent function, and only 2 had moderate impairment. Function loss was most marked in leisure (25 patients) and vocational (8) activities, but was mild in 66% of cases. Multivariate analysis was carried out to determine the prognostic factors for poor limb function. The results suggested that overall functional score was predominantly determined by gait (P less than 0.001), muscle power or range of movement (P less than 0.001), with increasing age, female sex and the use of radiotherapy poor prognostic factors. Reduced muscle power or range of movement were the major factors determining gait (P less than 0.02) with the use of radiotherapy the significant prognostic factor for both in the conventionally treated group. Doses in excess of 60 Gy resulted in increased fibrosis and a worse functional outcome. Extent of surgery was not an independent prognostic factor for limb function, although univariate analysis suggested an association with range of movement in the conventionally treated group (P less than 0.025). Despite significant objective loss of range of movement and muscle power patients retain excellent limb function and quality of life following limb conserving treatment. For optimal function, radiotherapy should be given with small fractions to a dose not exceeding 60 Gy.

A prospective randomized trial of adjuvant chemotherapy with bolus versus continuous infusion of doxorubicin in patients with high-grade extremity soft tissue sarcoma and an analysis of prognostic factors

A prospective randomized trial was conducted to compare the cardiotoxic and therapeutic effects of doxorubicin (60 mg/m2 every 3 to 4 weeks) administered by bolus or 72-hour continuous infusion as adjuvant chemotherapy in 82 eligible patients after resection of high-grade soft tissue sarcoma of the extremity or superficial trunk. Cardiac toxicity, defined as a 10% or greater decrease in left ventricular ejection fraction as assessed by radionuclide cineangiography, was evaluated in 69 patients. Cardiotoxicity was seen in 61% of patients in the bolus treatment arm with the median doxorubicin dose of 420 mg/m2. Among patients who received continuous infusion, 42% had cardiotoxicity with a median dose of 540 mg/m2. The rate of cardiotoxicity as a function of the cumulative dose of doxorubicin was significantly higher in the bolus treatment arm (P = 0.0017). Two patients in each group had clinical congestive heart failure, with one cardiac death occurring in each. There was a trend toward a lower rate of metastasis (P = 0.19) and a significantly lower rate of death of disease (P = 0.036) for patients treated with the bolus dose. Cox model analysis identified three unfavorable characteristics for the rate of developing a distant metastasis: blood transfusion within 24 hours of operation (P less than 0.00001), tumor deep to the fascia and 5 cm or more in size (P = 0.0043), and a histologic subtype other than liposarcoma (P = 0.0002). The unfavorable effect of continuous infusion was not selected in the model (P = 0.16). Adjuvant chemotherapy for patients with soft tissue sarcoma is investigational. Furthermore, the impact of perioperative blood transfusion merits further study.

The survivors of childhood solid tumors

With the improvement in cancer therapy in recent years, the number of cancer survivors is rapidly increasing. Potential late medical and psychosocial sequelae of cancer therapy are reviewed. A practical guide for the primary health care giver is provided.

Prospective evaluation of chronic cardiotoxicity due to high-dose epirubicin or combination chemotherapy with cyclophosphamide, methotrexate, and 5-fluorouracil

In a prospective study the left ventricular ejection fraction (LVEF), right ventricular ejection fraction (RVEF), systolic blood pressure, ECG, and heart rate were recorded at rest and during submaximal work to compare the cardiotoxic effect of epirubicin with a combination chemotherapy without known cardiotoxicity. A total of 14 females with advanced breast cancer were treated with epirubicin at a median cumulative dose of 827 mg/m2 (range, 550-1244). These patients had previously received cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) or cyclophosphamide alone as adjuvant treatment, or CMF for advanced disease. The control group consisted of 11 females with advanced breast cancer given CMF only. The systolic blood pressure at rest as well as during submaximal work was significantly lower (P less than 0.05) after treatment in the epirubicin group than in the CMF controls. With regard to LVEF, the median value of 54% at rest was significantly lower after treatment in the epirubicin group than in the controls (59%). There was a significant fall in LVEF at rest and during exercise in the epirubicin group, whereas no such changes were found in the CMF controls after treatment. The RVEF was unaffected. In the epirubicin-treated group one patient developed fatal congestive heart failure, and in the remaining 13 patients treatment was discontinued due to progression of the cancer and not to cardiotoxicity. Thus, the cardiotoxicity of epirubicin changed the clinical outcome in only 1 of 14 patients with advanced breast cancer.

Modulation of the calcium release channel of sarcoplasmic reticulum by adriamycin and other drugs

The calcium release channel of sarcoplasmic reticulum mediates Ca2+ release which triggers muscle contraction in excitation-contraction coupling. The channels have been identified morphologically with the feet structures, which are involved in junctional association of terminal cisternae of sarcoplasmic reticulum with the transverse tubules to form the triad junction. In this study, we further characterize the action of drugs on the calcium release channel from sarcoplasmic reticulum fused into planar bilayers. Adriamycin is an effective cancer chemotherapeutic drug, which is limited by its cardiotoxicity. The drug, when added to the myoplasmic side (cis side), activates channel opening at microM concentrations in a dose dependent manner. Adriamycin together with ATP (mM) gives optimal activation, with an open probability (Po) of approximately 1.0. Ruthenium red added to the cis side, equivalent to the cytoplasmic (myoplasmic) domain, completely blocks channel opening. Qualitatively similar results are obtained with adriamycinol, the major metabolite of adriamycin. The inhibition by adriamycin is not reversed by reperfusion to wash out the drug. Silver ions are also found to activate the channel. The conductance of the channel activated by adriamycin, adriamycinol or Ag+ is approximately 100 ps, similar to that previously reported for activation of the channel with Ca2+ and ATP. Ruthenium red has previously been observed to block channel activation from the cytoplasmic side.(ABSTRACT TRUNCATED AT 250 WORDS)

Doxorubicin cardiotoxicity may be caused by its metabolite, doxorubicinol

Doxorubicin (former generic name, adriamycin), a highly effective anticancer drug, produces cardiotoxicity, which limits its therapeutic potential. The mechanism of this cardiotoxicity has remained elusive. Our data suggest that this toxicity could involve doxorubicinol, the primary circulating metabolite of doxorubicin. Doxorubicinol was markedly more potent than doxorubicin at compromising both systolic and diastolic cardiac function. Similarly, doxorubicinol was much more potent than doxorubicin at inhibiting the calcium pump of sarcoplasmic reticulum [ATP phosphohydrolase (Ca2+-transporting), EC 3.6.1.38], the Na+/K+ pump of sarcolemma [ATP phosphohydrolase (Na+/K+-transporting), EC 3.6.1.37], and the F0F1 proton pump of mitochondria [ATP phosphohydrolase (H+-transporting, EC 3.6.1.34]. Our finding that this highly toxic metabolite was produced by cardiac tissue exposed to doxorubicin suggests that doxorubicinol could accumulate in the heart and contribute significantly to the chronic cumulative cardiotoxicity of doxorubicin therapy. Our observation that doxorubicin was more potent than doxorubicinol in inhibiting tumor cell growth in vitro suggests that the cardiotoxicity of doxorubicin is dissociable from its anticancer activity.