Head and neck radiotherapy - A risk factor for anaesthesia?

BACKGROUND: The aim was to study perioperative management in head and neck cancer, the commonest cancer in Indian men, after radiation therapy. Radiotherapy (RT) targets the tumour and the neck including the thyroid gland. RT induced physical effects (on the airway) and physiological effects (on the thyroid) impact perioperative care. Patients with RT-induced subclinical and mild clinical hypothyroidism are often asymptomatic. Cancer surgery is time-sensitive. Given that parenteral levothyroxine is not available, is a TSH of 15 acceptable for cancer surgery? METHODS: A retrospective study was conducted in a tertiary cancer centre. The records of elective surgery (72 patients) were scrutinised. Data on thyroid profile, airway, treatment of clinical and subclinical hypothyroidism, airway access, recovery and perioperative haemodynamic parameters were retrieved. Correlation of age, sex, RT, chemotherapy with hypothyroidism was done by Chi-square test. The perioperative course was studied. RESULTS: Hypothyroidism (subclinical and clinical) was diagnosed in 39% of patients. All were asymptomatic. There was a significant association between RT and hypothyroidism. In 50% of patients, we encountered a difficult airway. In subclinical hypothyroidism (TSH less than 15), after levothyroxine initiation, the course of anaesthesia, extubation, recovery and postoperative stay was uneventful. CONCLUSIONS: Hypothyroidism and difficult airways are a common sequel of RT. Selected cancer patients with subclinical hypothyroidism had a smooth perioperative course.