Adverse effects of radioactive iodine-131 treatment for differentiated thyroid carcinoma.
Introduction: Differentiated thyroid cancer (DTC) is the most common endocrine malignancy. This malignancy generally has an excellent prognosis with more than 90% long term survival. Consequently, life quality improvement is the first priority especially in the young DTC survivors. In classic management of a new DTC patient, each therapeutic modality can significantly induce morbidities. In the current study, we investigated the main complaints in DTC patients during the follow up. Methods: Clinical symptoms of 300 randomly selected DTC patients were collected during their follow up visiting sessions. Related symptoms were any clinical complaint directly due to DTC or its management. The correlation between the most common complaint and age, gender, TNM staging, RAI therapy, external beam radiotherapy and neck surgery was assessed. Results: Three hundred randomly selected DTC patients (66 male and 234 female) were included. The mean duration of follow up was 5.18±3.48. External radiotherapy of the neck, frequency of radioiodine therapy and repetitive neck operations were associated with more clinical symptoms during long term follow up. The most frequent DTC related complaint was neck discomfort which was reported in 40% of patients. The main background source of patients' complaints was hypothyroidism followed by subclinical hyperthyroidism (p<0.01). Conclusion: The most common reasons of long term morbidity in DTC patients were related to hypothyroid or subclinical hyperthyroidism. Neck discomfort was the most frequent single complaint with more frequency in patients with repetitive neck operation. The current study could be the first step to discover the unfavorable clinical symptoms of DTC patients.