Examining the Long-term Health of Thyroid Cancer Survivors

Study: Thyroid cancer survivors – especially those diagnosed before age 40 – had elevated risk for several aging-related diseases.

Cancer survivors are living longer today than ever before, and they need to be aware of long-term disease risks, according to Mia Hashibe, PhD, the lead author of a recent study published recently in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.

“Thyroid cancer survivors are a group we are particularly concerned about for long-term health issues, since thyroid cancer is often diagnosed at an earlier age than other cancers, and the five-year survival rate is very high, at 98 percent,” said Dr. Hashibe, an associate professor in the Department of Family and Preventive Medicine at the University of Utah, Salt Lake City, and a Huntsman Cancer Institute (HCI) investigator.

After examining risk for 39 aging-related diseases, the researchers found that
thyroid cancer survivors had significantly increased risk for many of these diseases compared with age-matched, cancer-free individuals.

Moreover, for many diseases, including diabetes, cardiomyopathy, high blood pressure (hypertension), osteoporosis, and nutritional deficiencies, the increased risk was higher for those diagnosed with thyroid cancer before age 40 than for those diagnosed at older ages.

Dr. Hashibe hopes that this study will increase awareness of the long-term health issues experienced by thyroid cancer survivors so that they and their health care providers are proactive about having regular follow-ups and discussions about adopting a healthier lifestyle.

For the study, Dr. Hashibe and her colleagues analyzed electronic medical records, statewide health care data, voter registration records, residential histories, family history records, and birth and death certificates obtained from the
Utah Population Database, a research resource managed by the HCI, which contains an extensive collection of family histories linked to medical and demographic records. The researchers identified 3,706 people who had been diagnosed with thyroid cancer between 1997 and 2012, 37 percent of whom were under age 40 at diagnosis. For each of the thyroid cancer survivors, the researchers extracted data for up to five cancer-free individuals matched to the survivor by birth year, sex, and birth state.

Overall, thyroid cancer survivors had significantly increased risk for many of the 39 aging-related diseases examined. For example, all thyroid cancer survivors had significantly increased risk for hypertension and diabetes at all time points after diagnosis compared with age-matched, cancer-free individuals. For most of the other diseases, risk was increased at some time after diagnosis for either the group diagnosed at a young age or an older age.

For many diseases, including diabetes, cardiomyopathy, hypertension, osteoporosis, and nutritional deficiencies, the increase in risk was higher for those diagnosed with thyroid cancer before age 40 than for those diagnosed at older ages. For example, survivors diagnosed before age 40 had an almost eightfold increased risk of osteoporosis one to five years after diagnosis compared with age-matched, cancer-free individuals, while survivors diagnosed at older ages had a twofold increase in risk of osteoporosis compared with age-matched, cancer-free individuals.

Dr. Hashibe explained that the more aggressive treatment often given to younger patients may contribute to the observation that risk for some of the aging-related diseases appeared to be higher for those diagnosed before age 40 than for those diagnosed at older ages.

It is important to note that this is a retrospective, observational study. One of its limitations is that detailed information on treatment was limited, making it hard to determine the effects of specific treatments on risk.

This study was supported by funds from National Institutes of Health, the National Cancer Institute, the Huntsman Cancer Foundation, the Utah State Department of Health, and the University of Utah.