Persons with differentiated thyroid carcinoma (DTC) are at heightened risks for cardiovascular and all-cause mortality independent of age, sex, and cardiovascular risk factors, researchers have learned.

Most thyroid cancers are differentiated cancers, according to information from the American Cancer Society. These cancers (such as papillary carcinoma and follicular carcinoma) develop from thyroid follicular cells and closely resemble normal thyroid tissue on microscopic examination. Although the prognosis for DTCs typically is good, Joop D. Lefrandt, MD, PhD, of the University Medical Center Groningen in Groningen, the Netherlands, and colleagues now have shown that patients are at increased risk for cardiovascular death or death from other causes.

This finding emerged from a retrospective comparison conducted by Lefrandt’s team and reported in Journal of Clinical Oncology. Their study involved 524 patients with DTC and 1,572 sex- and age-matched controls from a large population-based study in the same geographic region. The mean age of the patients was 49 years; median follow-up was 8.5 years for the DTC group and 10.5 years for the controls.

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Throughout follow-up, 100 persons with DTC (19.1%) died: 39 patients (7.4%) from DTC, 22 (4.2%) from cardiovascular disease, and 39 (7.4%) from other/unknown causes. In comparison, 85 controls (5.4%) died, 24 (1.5%) as a result of cardiovascular disease and 61 (3.9%) as a result of other/unknown causes.

After the data were adjusted for age, sex, and cardiovascular risk factors, patients with DTC were found to be more than three times more likely than controls to die from cardiovascular disease (hazard ratio [HR] 3.35), and nearly 4.5 times more likely to die from any cause (HR 4.40).

In the DTC group, a lower thyroid-stimulating hormone (TSH) level was predictive for cardiovascular mortality: The adjusted HR was 3.08 for each 10-fold decrease in geometric mean TSH level. Lefrandt and coauthors pointed out that this finding supports current guidelines from the American Thyroid Association and the European Thyroid Association, which recommend tempering TSH suppression in patients who are at low risk of cancer recurrence.

The investigators also noted that persons with DTC may benefit from assessment and treatment of cardiovascular risk factors.