Cancer Drugs Can Cause Heart Damage (From Joyce)

[dadstimeon]

Joyce (endangered but surviving) asked me to post this for her. Thanks for sharing Joyce, very interesting. Rich

http://www.cancerwise.org/september_200 ... &color=red

Cancer Drugs Can Cause Heart Damage

Some Doctors Do Not Fully Protect Against Complications

Any cancer drug can cause potential heart damage, even death, and many doctors do not adequately monitor their patients or manage their care to minimize the health risk, according to a study by M. D. Anderson cardiologists.

“Patients and doctors may not be aware of the spectrum of heart problems that can arise from cancer treatment, or know that many of these problems can be managed,” says the study’s lead author, Edward T. H. Yeh, M.D., professor and chairman of the institution’s Department of Cardiology.

The study, published in the June 29 issue of the journal Circulation, is the first large-scale review that details:

Cardiovascular complications that often occur in cancer therapy

Ways to prevent or treat heart problems resulting from cancer treatment

Conducted with nine other M. D. Anderson cardiologists, the study reviews research on the cardiotoxicity (toxic effects on the heart) of 29 anti-cancer drugs as well as 30 years of experience at M. D. Anderson.

Cardiotoxicity can occur in any patient, Yeh says. Generally speaking, however, patients most at risk are elderly and have other illnesses, such as diabetes and heart disease. Heart problems can occur during treatment or months and even years after treatment.

Potential problems described for each drug

Even the newest targeted therapies, designed to attack only cancer cells, can cause cardiotoxicity, Yeh says. The following potential problems can exist with these cancer medications:

Monoclonal antibodies – These substances locate and bind to cancer cells and can be used alone, or to deliver drugs, toxins, or radioactive material directly to tumor cells.

Toxic effects of these drugs (Avastin, Erbitux, and Rituxin) include:

Hypertension (high blood pressure)

Hypotension (low blood pressure)

“They seem to have more general toxicity than many other agents, but the problems they produce usually involve changes in blood pressure, which can be easily treated if recognized,” Yeh says.

The monoclonal antibody Herceptin is less toxic than generally believed, although it can cause:

Chronic heart failure

Dysfunction of the left ventricular, the main chamber of the heart that pumps blood to the body

Chemotherapy drugs – Heart problems are relatively rare in the “antimicrotubules” class of chemotherapy drugs, of which Taxol is a member. However, several other common classes of chemotherapy drugs can cause potential heart damage:

Anthracyclines/anthraquinolones – (adriamycin). These agents are clearly more toxic to the heart than other medications, especially in large doses. They should be closely monitored because they frequently produce:

Irreversible chronic heart failure

Left ventricular dysfunction

“This is probably the most problematic class of anticancer drugs, but with experience, cardiotoxicity can be limited,”Yeh says.

Alkylating agents – Platinol and Cytoxan, the most widely used alkylating agents, can produce a wide range of heart problems at higher doses, including:

Chronic heart failure

Hypertension

Antimetabolites – (which include the widely used agent 5-fluorouracil). Antimetabolites can produce ischemia, a decreased flow of oxygenated blood to an organ due to an obstruction in an artery, which can lead to heart attacks if not treated.

Non-chemotherapy drugs – Potential heart damage also can occur with:

Interleukin-2 – which frequently results in:

Hypotension (low blood pressure)

Arrhythmias (irregular heartbeat)

Gleevec – which can cause heart failure

Trisenox – which can result from fatal “QT prolongation” (lengthening of the part of the heart rhythm cycle referred to as the QT interval.)

Thalidomide – which can produce a variety of serious heart ailments

Yeh says although the potential for heart damage from cancer drugs is present, complications can be avoided with proper measures.

Possible solutions include:

Avoiding certain drugs

Lowering drug dosages

Administering drugs slower and over a longer period of time

Monitoring cardiac health more stringently

Avoiding giving some drugs simultaneously

Treating cardiac risk factors

Use of an echocardiogram during and after cancer treatment

Treating patients with heart failure drugs

“We found a profile of cardiotoxicity for the most often used anticancer drugs, but it is important to know that every patient has different risk factors that will determine how their hearts handle the treatment,” Yeh says. “Monitoring and management is key to surviving cancer with a good and lasting heart.”

[gpawelski]

The fact that proving efficacy and toxicity in one situation does nothing to prove efficacy and toxicity in any other situation. This is why the FDA demands clinical trials showing data for each and every indication relating to drugs.

Some common chemotherapeutic agents (paclitaxel, doxorubicin, and trastuzumab) can trigger hypertension or problems with the heart, such as arrhythmias, congestive heart failure, or bradycardia. There are some, like 5-FU [fluorouracil] and Xeloda [capecitabine], that can cause chest pains, resulting from spasms of the arteries that go to the heart. Many patients on chemotherapy become anemic, and that can trigger further cardiac complications. Other agents affect the kidneys, sometimes to the point of requiring dialysis. In addition, because many patients on chemotherapy are immunocompromised, pulmonary infections are quite common.

By analyzing non-cancer deaths among cancer patients, it becomes clear that orthodox therapies often do more harm than good. For example, cancer treatment can damage the heart and cause deaths from heart failure. This means fewer deaths from cancer. Analysis of the records of 1.2 million cancer cases in the Surveilance, Evaluation and End Results (SEER) database showed that non-cancer deaths accounted for 21 - 37 percent of all deaths. The authors attributed this effect to the damage caused by cancer treatment.

I believe that any true randomized clinical trial (where it has been shown that a group treated with chemotherapy experienced significantly increased survival when compared with that of an untreated group) would show the SEER figures to be too low. In clinical trials, many patients are excluded because they could not complete the rather arduous treatment. So randomized comparisions are of healthier treated patients against all the controls, rendering a lot of trials invalid.

Any cancer drug can cause potential heart damage, even death, and many doctors do not adequately monitor their patients or manage their care to minimize the health risk. Patients and doctors may not be aware of the spectrum of heart problems that can arise from cancer treatment. Heart problems can occur during treatment or months and even years after treatment. So yes, even the newest "targeted" therapies, designed to attack only cancer cells or microvascular cells, can cause cardiotoxicity.

Some clinical scientists have found a profile of cardiotoxicity for the most often anticancer drugs, but it is important to know that every patient has different risk factors that will determine how their hearts handle the treatment. Monitoring and mangement is key to surviving cancer with a good and lasting heart.

Many of these new "targeted" therapies often get a pass on toxicities because they are just so darn cool (Herceptin and CHF in the adjuvant setting is another example). The problem is that few drugs work the way oncologists think and few of them take the time to think through what it is they are using them for.