P-043. IGF-I measurement in post-operative evaluation of patients with tumours of the sellar region

Hypopituitarism is frequent in patients operated for tumours of the seller region and impairement of GH secretion is usually the first marker of pituitary dysfunction. The sensitivity of IGF-I as a peripheral marker of GH secretion in the post-operative evaluation of pituitary function was studied in 35 patients after surgery for non-pituitary tumours (n = 20, including 11 craniopharyngiomas) and non-GH secreting pituitary macroadenomas (n = 15). Only four craniopharyngioma patients received post-operative radiation therapy. Plasma IGF-I was determined by VIA after acid-ethanol extraction. Results: Age-corrected IGF-I values were under the normal range in 15/20 patients with extra-pituitary tumours and in 8/15 patients with pituitary tumours, respectively. IGF-I values revere significantly correlated with tumour type (p<0.01), the lowest values being observed in patients with craniopharyugiomas (45.8 ± 7.0 ng/ml) and the highest in patients with pituitary adenomas (88.8 ± 10.6 ng/ml), respectively. IGF-I values were also correlated with the degree of pituitary dysfunction (p<0.001). the lowest values being observed in patients with multiple pituitary hormone deficiencies. No correlation was found between IGF-I values and patient's age. Among patients presenting at least another pituitary hormone deficiency, IGF-I was low in all subjects aged <45 years old (11/11) whereas values overlapping with the normal range were observed in 8/16 patients aged > = 45 years old (p<0.01), indicating a higher sensitivity of IGF-I in young patients. Conclusion: IGF-I appears to be a good marker of hypopituitarism in young patients operated on for tumours of the seller region, possibly avoiding the need for dynamic evaluation of GH secretion in such patients. Additional criteria should be considered in most patients aged >45 years old.