This study evaluated the incidence of thyroid dysfunction in patients receiving radiotherapy (RT) or chemoradiotherapy (chemo-RT) for non-thyroid head and neck cancers. The study found that 20% of patients developed subclinical hypothyroidism, with most cases occurring within 6-12 months after treatment completion. Patients with hypopharyngeal tumors, T3 stage, N2 nodal involvement, or stage IV disease had a higher risk of developing subclinical hypothyroidism. While no patients showed clinical signs of hypothyroidism, many reported fatigue, indicating potential future overt hypothyroidism. Close monitoring of thyroid function was recommended.

1. THYROID DYSFUNCTION IN PATIENTS TREATED WITH RT / CHEMO-RT FOR NON-THYROID HEAD & NECK CANCERS Dr.T.Sujit Dr. V.Nagarajan MD , DMRT HoD , Radiation Oncology Dr.M.Nagarajan MD , DNB Consultant Radiation Oncologist G.KUPPUSWAMY NAIDU MEMORIAL HOSPITAL , COIMBATORE

13. 100.0 80.0 20.0 % 50 40 10 Count TOTAL 2 2 0 Count Others 2 2 0 Count Unknown primary 8 2 6 Count Hypopharynx 10 10 0 Count Larynx 16 14 2 Count Oro-pharyn 12 10 2 Count Oral cavity No Yes Total HYPOTHYROID PRIMARY SITE 100.0 80.0 20.0 % 50 40 10 Count Total 2 2 0 Count TX 6 6 0 Count T4 18 12 6 Count T3 22 18 4 Count T2 2 2 0 Count T0 No Yes Total HYPOTHYROID T STAGE

14. 100.0 80.0 20.0 % 50 40 10 Count Total 6 4 2 Count N3 8 4 4 Count N2 26 22 4 Count N1 10 10 0 Count N0 No Yes Total HYPOTHYROID N STAGE 100.0 80.0 20.0 % 50 40 10 Count Total 16 10 6 Count STAGE 4 22 18 4 Count STAGE 3 12 12 0 Count STAGE 2 No Yes Total HYPOTHYROID STAGE GROUPING