Thyroid dysfunction following radiotherapy for head and neck cancer

The Shrinking Thyroid: How Does Thyroid Size Change Following Radiation Therapy for Laryngeal Cancer?

“…[1][2][3][4][5][6][7][8][9][10][11][12] XRT causes microvascular and parenchymal damage to the gland, which results in decreased function several years after completing XRT. Eighty-five percent (52/61) of the patients included in this study demonstrated a measured decrease in the width of the thyroid gland on follow-up CT, with measurable changes occurring in several patients within the first quarter year following completion of XRT.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12] The percentage of patients developing hypothyroidism during the study period is likely exaggerated because lack of clinical data on thyroid function was an exclusion criterion for the study. A disproportionate number of euthyroid patients were probably excluded because it may be easier to document positive signs and symptoms of a disorder rather than negative signs and symptoms.…”

“…Hypothyroidism is documented in approximately 20%-67% of patients receiving XRT for Hodgkin or non-Hodgkin lymphoma and approximately 20%-31% of patients receiving XRT for head and neck cancers in the first 5 years after treatment. [1][2][3][4][5][6][7][8][9][10][11][12] Hypothyroidism typically occurs within 5 years after completing XRT. Morphologic changes to the thyroid gland after XRT, such as the development of solid or cystic masses, are well documented by sonography and histology.…”

The potential of proton beam radiation therapy in head and neck cancer

“…Hearing impairment with or without otorrhea, fibrosis of the neck and temporal lobe necrosis is reported following ERBT alone of nasopharyngeal carcinoma [32]. Thyroid dysfunction is reported to be as common as 40% in patients 5 years after radiotherapy for H&N cancer and thyroid function testing is therefore suggested to be part of routine post-treatment follow-up of this patient category [33]. Radiation induced secondary cancers appear both after radioisotope therapy for thyroid cancers and after EBRT of H&N cancers [34], and there are also reports describing an increased risk due to the implementation of the new techniques 3D-CRT and especially IMRT [35,36].…”

Post-radiotherapy hypothyroidism in head and neck cancers: When should we be concerned?

“…Routine assessment of thyroid function in follow-up is not commonly undertaken in patients receiving RT for HNC, which may result in failure to detect and treat a reversible cause of morbidity for a significant proportion of surviving patients. [2] Hypothyroidism after RT alone or in combination with surgery and/or chemotherapy for HNCs has been well reported between 17% and 51% in the literature. [3][4][5][6] However, thyroid dysfunction after RT for HNC still represents a clinically underestimated problem.…”