Risk Factors ID'd for Radiation-Induced Hypothyroidism
Female gender, neck surgery up risk; Caucasians at higher risk than African-Americans
WEDNESDAY, Nov. 30 (HealthDay News) -- Factors associated with an increased risk of radiation-induced hypothyroidism (RIHT) include female gender and surgery involving the thyroid gland or other neck surgery, with Caucasians at increased risk compared with African-Americans, according to a meta-analysis published in the Dec. 1 issue of Cancer.
Ivan R. Vogelius, Ph.D., from the University of Copenhagen in Denmark, and colleagues reviewed available literature to identify risk factors for the development of hypothyroidism (HT) after radiation therapy. Studies included those that permitted the extraction of odds ratios (ORs) for HT in candidate clinical risk groups. Meta-analyses were carried out for the development of HT with or without each candidate risk factor, and for the dose-response curve.
The investigators found that female gender was significantly associated with an increased risk of HT (OR, 1.6), as was having surgery involving the thyroid gland (OR, 8.3), or other neck surgery (OR, 1.7). Compared to African-Americans, Caucasians had a significantly increased risk of HT (OR, 4.8). A correlation was seen between lymphangiography and HT, but there was evidence of publication bias. A radiation dose-response relationship was seen, with a 50 percent risk of HT at a dose of 45 Gy, but there was considerable between-study variation in the dose response. No correlation was found between the risk of HT and chemotherapy or age.
"Female gender and surgery, involving the thyroid gland or not involving the thyroid gland, are associated with a higher risk of RIHT. In addition, Caucasians are at higher risk of RIHT than African-Americans," the authors write.