Thyroid Cancer Occurring as a Late Consequence of Head-and-Neck Irradiation

TLDR

The study retrospectively examined 1,056 of 5,266 patients who received therapeutic head‑and‑neck irradiation for upper respiratory tract infections in the 1940s–1950s, with 85% treated at the tonsillar and nasopharyngeal sites. Among the examined cohort, 27.2% had nodular thyroid disease, of which 33% of operated cases were malignant, and the data suggest a strong association between head‑and‑neck irradiation and long‑term thyroid nodularity, indicating a persistent health risk for at least 35 years.

Abstract

From January 1 to September 30, 1974, we examined 1056 of 5266 subjects (20.1%) who had received therapeutic irradiation primarily for infections and inflammatory disease of the upper respiratory tract at our institution during the 1940's and 1950's. The tonsillar and nasopharyngeal region was the treatment site in 85% of those examined. Palpable nodular thyroid disease was found in 16.5%, and nonpalpable lesions were detected by 99m Tc pertechnetate thyroid imaging in an additional 10.7%, for a prevalence of nodular disease of 27.2%. Operation on 71% with nodular disease revealed thyroid cancer in 33% (60 of 182). Preliminary analysis for potential risk factors suggests a correlation between radiation exposure and the presence of thyroid nodules (P less than 0.001). These findings indicate that nodular thyroid disease, both benign and malignant, continues as a major health problem for at least 35 years in exposed subjects.