Coronary angioplasty tied to leukemia risk

By Marilynn Larkin

NEW YORK (Reuters Health) - Percutaneous transluminal coronary angioplasty (PTCA) is associated with an increased risk of leukemia, researchers from Taiwan report.

The team analyzed registry data for more than 5,000 patients with leukemia and 20 times as many cancer-free control patients, matched for age and sex. All participants were retrospectively surveyed (from the year 2000) to determine whether they received cardiac fluoroscopic interventions.

After adjusting for age, gender, and comorbidities, PTCA was associated with a significantly increased risk of leukemia with an adjusted odds ratio of 1.57; coronary angiography alone without PTCA and cardiac electrophysiologic study were not associated with increased risk.

In addition, an increased frequency of PTCA and coronary angiography was associated with significantly higher risks of leukemia (adjusted OR, 1.33 to 1.53). A gender subgroup analysis demonstrated a higher risk for men compared with women, the authors report in the March issue of Medicine.

In a joint email, coauthors Drs. Chung-Yi Li, Wen-Yen Chiou and Kai-Che Wei of National Cheng Kung University in Tainan, told Reuters Health, "Our observational study noted a higher incidence of leukemia in patients who underwent cardiac angiographic catheterization. The difference in risk became statistically significant within as early as three years following the procedure. Noticeably, there was a trend towards an increased incidence of leukemia with more frequent PTCA and angiography performed."

"In addition, cardiologists, radiologists and hospital administrators should acknowledge the possible harms of repeated radiation exposure and avoid procedures requiring long time radiation exposure," the researchers said. "They should also take action to decrease unnecessary radiation exposure as much as possible with the aid of medical dosimetrists and medical physicists."

They added that "the informed consent for cardiac fluoroscopy should include the information on possible complications of radiation exposure, such as skin ulcer, cataract, or a malignancy such as breast cancer, lung cancer and leukemia in particular. Patients and their family should be well informed of the potential carcinogenic risk associated with (these) interventions."

Dr. Samir Kapadia, an interventional cardiologist at Cleveland Clinic, told Reuters Health that "this particular study has limitations. For example, the authors did not know the radiation dose participants received or if they had other types of radiation exposure, such as CT scans. Nevertheless, awareness about radiation side effects is an important, relevant message, both for patients and physicians."

"The public should be aware that radiation exposure is an important hazard. They should be aware of how much radiation they're having - especially the cumulative dose if they're having more than one procedure - because it all adds up."

Dr. Kapadia added that it's not possible in the U.S. to know a patient's lifetime radiation dose because that information is not included in electronic medical records. Therefore, at Cleveland Clinic, "we are trying to implement a way to add radiation dose to the record each time someone has a procedure. It is very critical and real problem, and there's enough data from other sources to say radiation can cause cancers and we should try to minimize it."

The Taiwanese team and Dr. Kapadia agree that this study should not be interpreted as a warning not to undergo PCTA.

In their email, the authors observe, "The net benefits of PTCA for heart disease are believed to outweigh the potential risk of malignancy associated with PTCA."

SOURCE: bit.ly/1RfTnoL

Medicine 2016.

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