How common is hypothyroidism after external radiotherapy to neck in head and neck cancer patients?

Abstract

Purpose:To identify the occurrence of clinical and subclinical hypothyroidism among head and neck cancer patients receiving radiation to the neck and to justify routine performing of thyroid function tests during follow-up.Materials and Methods:This is a prospective nonrandomized study of 45 patients of head and neck cancer, receiving radiotherapy (RT). Thyroid stimulating hormone and T4 estimations were done at baseline and at 4 months and 9 months following RT.Results:Of the 45 patients, 37(82.2 %) were males and eight (17.8 %) were females. All patients received radiation to the neck to a dose of >40Gy. 35.6% received concurrent chemotherapy. Two patients underwent prior neck dissection. Fourteen patients (31.1%) were found to have clinical hypothyroidism (P value of 0.01). Five (11.1%) patients were found to have subclinical hypothyroidism with a total 19 of 45 (42.2%) patients developing radiation-induced hypothyroidism. Nine of 14 patients with clinical hypothyroidism were in the age group of 51 to 60 years (P=0.0522). Five of 16 patients who received chemoradiation and nine of 29 who received RT alone developed clinical hypothyroidism. Above 40 Gy radiation dose was not a relevant risk factor for hypothyroidism.Conclusion:Hypothyroidism (clinical or subclinical) is an under-recognized morbidity of external radiation to the neck which is seen following a minimum dose of 40 Gy to neck. Recognizing hypothyroidism (clinical or subclinical) early and treating it prevents associated complications. Hence, thyroid function tests should be made routine during follow-up.

Evaluation of Thyroid Dysfunction in Patients with Head and Neck Cancer Receiving Radiation Therapy or Chemoradiation

“…12,25,26 Only Tell et al 17 found that increasing age was correlated with an increased risk of hypothyroidism. In a study by Srikantia et al, 27 52.9% of the patients who developed clinical hypothyroidism were between the age groups of 51 to 60 years. In our study, the occurrence was definitely higher in patients older than 45 years of age.…”

Head and neck radiotherapy - A risk factor for anaesthesia?

“…[ 11 ] Development of clinical hypothyroidism occurs at a rate of about 5 to 20% per year. [ 12 ] Clinical hypothyroidism typically manifests by slow mentation, depression, dry skin, pleural and pericardial effusions, decreased gastrointestinal motility, weight gain, cold intolerance, chronic fatigue, congestive heart failure, decreased wound healing and acceleration of atherosclerosis. [ 9 ] None of our patients had any of these symptoms.…”

“…Srikantia et al . found that[ 12 ] 52.9% of the patients developing clinical hypothyroidism were 51 to 60 years old. ( P = 0.0522); however, the mean patient age analysed were in the range of 52 years.…”

Avaliação de toxicidades tardias em pacientes com carcinoma epidermoide de cabeça e pescoço submetidos a quimiorradiação concomitante baseada em cisplatina

“…, disfunção faringo-laríngea (disfagia e aspiração, 25%), hipotireoidismo (42%), ototoxicidade (27%), fístula/necrose cutânea (29%) e osteorradionecrose (4%) (33,34) .…”

“…O tempo para o desenvolvimento do hipotireoidismo é variável mas considera-se um intervalo mediano de 1,4 a 1,8 anos, com variação de 0,3-7,2 anos (83)(84)(85) e estima-se uma incidência entre 7,2-53% ao longo de 3 a 5 anos de seguimento (34,(82)(83)(84)(86)(87)(88)(89)(90)(91) . Uma revisão sistemática da literatura que avaliou 971 pacientes, a maioria deles tendo sido irradiada para CECCP, encontrou uma incidência de hipotireoidismo subclínico de 26 a 53% e de hipotireoidismo de 11 a 33% (92) .…”