Hypopituitarism after radiotherapy for extracranial head and neck cancers.
BACKGROUND
The purpose of this study was to investigate the incidence of radiotherapy-induced primary and secondary hypopituitarism.


METHODS
Three hundred twelve patients treated with radiotherapy for extracranial head and neck tumors between 1964 and 2000 were evaluated. Radiotherapy doses to the hypothalamus and pituitary were estimated by reconstructing treatment plans.


RESULTS
Clinical hypopituitarism was observed in 44 (14.1%) patients after a median interval of 5.6 years. Hypothalamic dysfunction was reported in 14 patients after a median interval of 4.4 years. Neither fractionation nor adjuvant chemotherapy significantly impacted clinical hypopituitarism on multivariate analysis, but total dose to the pituitary was significant (p = .0228). Twenty-three of 68 (33.8%) patients tested for hypopituitarism demonstrated subclinical hypopituitarism. The 5- and 10-year rates of freedom from clinical hypopituitarism were 93% and 72%. The 5- and 10-year rates of freedom from subclinical hypopituitarism were 85% and 65%.


CONCLUSIONS
Clinical and subclinical manifestations of late radiation toxicity were observed in the hypothalamic-pituitary axis.
Bhandare
Niranjan
N
Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, Florida, USA.
Kennedy
Laurence
L
Malyapa
Robert S
RS
Morris
Christopher G
CG
Mendenhall
William M
WM
D000328:Adult; D017677:Age Distribution; D000368:Aged; D000704:Analysis of Variance; D015331:Cohort Studies; D019583:Dose Fractionation, Radiation; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D006801:Humans; D007018:Hypopituitarism / Q000453:epidemiology* / Q000209:etiology*; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D017678:Sex Distribution; D016019:Survival Analysis