[Hypothyroidism following cervical irradiation in the management of carcinoma of the nasopharynx and of the breast: a prospective study on eighty-four cases].
OBJECTIVE
1/ To evaluate the incidence of hypothyroidism following radiotherapy in the management of breast and nasopharyngeal carcinomas, 2/ to define the role of a systematic post therapeutic screening.


METHODS
From January 1996 through March 2001 a systematic evaluation of the clinical and the biological thyroid function was performed on a cohort of 84 patients that received supraclavicular irradiation. Selected patients had either a mammary (37 cases) or a nasopharyngeal (47 cases) carcinoma. Initial work up included thyroid inspection and palpation, and biological tests: serum FT4 and TSH levels, radioimmunochemistry, completed by dynamic thyroid stimulation, using TRH, in case of border line low T4 or isolated high TSH levels. Tests were repeated every three months the first year, and then every six months. Replacement therapy with L Thyroxin was administered in case of hypothyroidism.


RESULTS
All selected patients had a normal function initially. With a mean two years follow up (1-5 years), 24 patients (29%) experienced hypothyroidism, half of whom (13 cases) being purely biological. Five patients (11%), with a nasopharyngeal carcinoma, presented also with associated pituitary failure. Clinical symptoms were minor or mild in all cases. Hypothyroidism was detected at a mean 21 months follow up. In 2 patients, hypothyroidism disappeared spontaneously within 6 months. Possible predictive factors were evaluated: age of the time of radiation, gender, percentage of irradiated thyroid, total dose, dose per fraction, tumour type and chemotherapy. Only age appeared significantly correlated with thyroid dysfunction (range: 10-30 years, P=0.002).


CONCLUSIONS
Hypothyroidism is a frequent and certainly underestimated complication following radiotherapy of the neck. In such patients, a systematic clinical and biological evaluation every three months the first year, and then every six months until five years is recommended.
Daoud
J
J
Service de radiothérapie carcinologique du CHU Habib Bourguiba de Sfax, Tunisie. jamel.daoud@rns.tn
Siala
W
W
Guermazi
F
F
Besbes
M
M
Frikha
M
M
Ghorbel
M
M
Drira
M
M
Abid
M
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000532:radiotherapy*; D002277:Carcinoma / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D007037:Hypothyroidism / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011446:Prospective Studies; D011832:Radiation Injuries / Q000175:diagnosis / Q000453:epidemiology; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000097:blood
D013963:Thyroid Hormones