February 9, 2011

Higher Cancer Risk After Cardiac Tests

(Ivanhoe Newswire) -- Cardiac imaging tests, such as CT scans could be putting heart attack patients at a higher risk of cancer.

According to a new study, exposure to low-dose radiation is associated with an increased risk of cancer. Typically, the amount of radiation that patients are exposed to is so small that it doesn't pose a major health risk, but when there are multiple scans the damage can start to add up.

Patients with known or suspected coronary artery disease, tend to have more frequent exposures to low-dose radiation procedures. In many places, radiation procedures are replacing non-radiation procedures like stress tests on exercise treadmills and echocardiography (a sonogram of the heart).

Between 1996 and 2006 researchers at MUHC and the Jewish General Hospital in Montr©al examined 82,861 heart attack patients who had no history of cancer. Seventy-seven percent underwent at least one cardiac procedure that exposed them to low-dose radiation within a year of the attack. Patients who were treated by a cardiologist had higher levels of exposure to radiation compared with those who were treated by a general practitioner. The findings showed about 12,000 incident cancers detected during follow up, and two-thirds of the cancers affected the abdomen and chest areas.

"These results call into question whether our current enthusiasm for imaging and therapeutic procedures after acute myocardial infarction should be tempered. We should at least consider putting into place a system of prospectively documenting the imaging tests and procedures that each patient undergoes and estimating his or her cumulative exposure to low-dose ionizing radiation," the authors were quoted as saying.

The authors say the best solution may be using procedures with lower or no radiation exposure, especially if there are multiple procedures involved.

SOURCE: CMAJ, February 7, 2011