Teenage, young adult cancer survivors may have increased risk of cardiac mortality

People who were diagnosed with cancer at 15 to 19 years old and survived for at least five years had a 4.2 times higher risk of cardiac mortality compared with the general population of people of similar age and gender, according to an analysis of survivors of teenage and young adult cancer in England and Wales.

Meanwhile, cancer survivors diagnosed from 35 to 39 years old had a 1.2 times higher risk of cardiac mortality compared with people their own age and gender.

Lead researcher Katherine E. Henson, DPhil, of the University of Oxford in the United Kingdom, and colleagues published their results online Nov. 7 in Circulation.

The researchers analyzed data from 200,945 people from the TYACSS (The Teenage and Young Adult Cancer Survivor Study), a population-based cohort trial. The patients were diagnosed with cancer from 15 to 39 years of age between 1971 and 2006. All patients survived at least five years.

“It is important for clinicians because it helps them focus the most intensive follow-up care on those most at risk,” Mike Hawkins, DPhil, a study co-author from the University of Birmingham in England, said in a news release. “It is important for survivors because it empowers them by providing them with their long-term chances of a specific side effect of cancer treatment.”

After a mean follow-up period of 14.3 years, 17 percent of patients died, including 6 percent whose deaths were attributed to cardiac disease. Of the cardiac deaths, 77 percent were due to ischemic heart disease, 11 percent were due to cardiomyopathy or congestive heart failure, 5 percent were due to valvular heart disease, 2 percent were due to rheumatic valvular heart disease, 1 percent were due to arrhythmias, 1 percent were due to pericardial heart disease and 3 percent were due to other cardiac causes.

The standardized mortality ratio for all types of cardiac disease was 1.4, while the absolute excess risk per 10,000 person-years was 1.9. The researchers noted that cardiac deaths accounted for 2 percent of the excess deaths. In additions, the proportion attributable to cardiac disease increased from 1 percent among people who were 20 to 39 years old and 4 percent among people who were at least 60 years old.

Hodgkin lymphoma survivors had the highest standardized mortality ratio (3.8) and absolute excess risk (12.9 per 10,000 person-years) for cardiac mortality. The other groups with significantly raised standardized mortality ratios for cardiac mortality were acute myeloid leukemia (2.7), genitourinary cancers other than bladder cancer (2.0), lung cancer (1.7), non-Hodgkin lymphoma (1.7), leukemia excluding acute myeloid leukemia (1.6), central nervous system tumors (1.4), cervical cancer (1.3) and breast cancer (1.2).

The standardized mortality ratio was highest (4.2) for patients diagnosed with cancer at 15 to 19 years old and lowest (1.2) for patients diagnosed at 35 to 39 years old. The absolute excess risk decreased from 3.6 per 10,000 person-years to 1.4 per 10,000 person-years, respectively.

The researchers mentioned a few limitations of the study, including that had limited information on whether the patients received radiotherapy or chemotherapy. They also did not know if patients smoked or had other cardiovascular risk factors.

“This study demonstrates for the first time that age at cancer diagnosis is important in determining the excess risk of cardiac death among an entire population of survivors of [teenage and yound adult] cancer,” the researchers wrote. “This age at diagnosis effect was primarily accounted for by survivors of Hodgkin lymphoma and breast cancer, providing useful risk stratification evidence. For evidence-based clinical follow-up of survivors estimates of risks that are reliable (from large-scale studies) and unbiased (from population-based studies) are needed for specific groups of survivors defined in terms of cancer type, age at cancer and type of treatment.”