Prevalence of pituitary hormone dysfunction following radiotherapy for sinonasal and nasopharyngeal malignancies

Background: There are limited studies and no surveillance protocols on pituitary dysfunction for adults who underwent anterior skull base radiation. Methods: Cross-sectional study of 50 consecutive patients with sinonasal or nasopharyngeal cancer who underwent definitive radiotherapy. The mean radiation doses, prevalence of pituitary dysfunction, and associated factors were calculated. Results: Pituitary hormone levels were abnormal in 23 (46%) patients, including 6 (12%) with symptomatic abnormalities requiring treatment. The most common hormonal abnormality was hyperprolactinemia (30%), central hypothyroidism (8%) and central hypogonadism (6%). Patients with abnormal pituitary hormone values received higher mean radiation doses to the pituitary gland (1143 cGy, P = 0.04), pituitary stalk (1129 cGy, P = 0.02), optic chiasm (1094 cGy, P = 0.01), and hypothalamus (900 cGy, P = 0.01). Conclusions: Nearly half of the patients had abnormal pituitary function, including over a tenth requiring treatment. There may be a dose-dependent association between hormonal dysfunction and radiation.