The added cancer risk from undergoing state-of-the-art heart scans may be trivial, according to Greek researchers. Over a lifetime, they estimate, about one in 4,000 women who've had their hearts examined once with the latest generation of computed tomographic (CT) scanners would develop cancer as a consequence.
Among men, the risk was less than one in 13,500. By comparison, about one in three Americans develop some type of cancer during their life. While the finding could ease concerns about the growing use of CT scans and the extra radiation that entails, the researchers still recommend that patients and their doctors always consider whether a test is really necessary.
"This shows us that radiation doses and cancer risks are coming down in heart imaging when we use some of the newer technologies now available," Dr. Andrew Einstein of the Columbia University Medical Center, who was not involved in the study, told Reuters Health. "That's a good thing."
CT scans are a non-invasive and precise way to image the heart's arteries. The newest scanners expose patients to far less x-ray radiation than older machines by monitoring the heartbeat and turning the beam on and off during the scan, explained Einstein.
Based on a study of 136 patients who underwent heart scans, John Damilakis of the University of Crete and his colleagues calculated the cancer risks linked to the radiation patients received. More than 90 percent were scanned with the most advanced machines and with the latest x-ray trimming technique, called prospectively gated CT.
The remaining patients received three to four times as much radiation during scans with the older machines. The researchers say women probably had a higher cancer risk because of the sensitivity of breast tissue to radiation. However, they still found that lung cancer was the more likely cancer among both men and women.
The cancer risks also appeared to vary based on body size and dropped with age at the time of testing, report the researchers in the journal Circulation. Depending on the specific type of scan, there would be an estimated 2 to 25 extra cases of cancer per 10,000 scans performed.
This contrasts with other recent research, which raised concerns about relatively high radiation doses with the tests.