Endocrine Abstracts

Introduction: Radiotherapy (RT) has been proven to be effective in controlling hormone production and tumor growth in pituitary adenomas (PA). Still, RT adverse effects had turned it an unattractive choice of treatment. The aim of this study was to evaluate the efficacy and safety of RT for patients with PA.

Methods: We conducted a retrospective study of patients treated in our center, a central hospital, since 1998. Thirty-three patients were included, 67% female, with a medium time of follow-up of 85.5 months (P25-44/P75-133 range 11–279). Twenty-nine patients had macroadenoma and 16 cavernous sinus invasion. Eight patients had pituitary deficits before RT. In all but one patient, RT was a secondary treatment after surgery. Eighteen patients had functioning PA (FPA) (11-GH, 6-ACTH, 1-PRL) and 15 non-functioning PA (NFPA) (7 null-cell, 3-FSH, 4-ACTH, 1-PRL).

Results: Twenty-eight patients were submitted to conventional or fractioned stereotaxic RT (mean daily dose 2.26±1.1Gy; mean dose 46.50±9.2Gy) and 5 patients were submitted to radiosurgery (mean dose 23±6.2Gy). Mean age on 1^st surgery was 43.31±13.4 years and at RT was 48.94±13.7 years. During follow-up patients presented: visual deficit deterioration (n=1,3.1%), new visual deficit (n=2,6.2%), hormonal deficit deterioration (n=3,37.5%), de novo hormonal deficit (n=14,58.3%), stroke (n=2,6.2%), cognitive impairment (n=6,18.8%) and death (n=2). Medium time to development of 1^st pituitary deficit was 19 months (P25-9/P75-42). Hypocortisolism and hypothyroidism were the most common deficits (n=13). In respect to NFPA, 2 did not achieve tumor growth control and 1 presented tumor growth, requiring new surgery. In respect to FPA: 4 achieved remission, 6 control with pharmacological treatment, 6 did not achieve biochemical control, 1 was lost to follow-up and 1 died. Medium follow-up time to biochemical control was 24 months (P25-11.5 P75-66). Nowadays, 10 patients are under pharmacological treatment. The overall estimated 6-month, 30-months and 108-months pituitary function preservation rates were 87.5%, 57.5% and 30.7%, respectively.

Conclusions: After RT, 86% of NFPA patients presented tumor growth control and 62.5% of FPA presented remission or biochemical control. RT-induced hypopituitarism was the most common adverse effect and hypocortisolism and hypothyroidism were the most common deficits. RT demonstrated to be an effective treatment in PA, nevertheless, it also presented important adverse effects. Life-long follow-up is essential in these patients and a longer follow-up is needed to evaluate long-term outcomes of RT in PA.