Treatment results of acromegaly as analyzed by different criteria.

Results of treatment of acromegaly are often incomparable due to the different criteria which have been used for defining cure or control of disease. At the present time it is widely accepted, that the main criteria of cure must be normalization of IGF-1 and a GH in the OGTT < 2 ng/ml. In this retrospective study we investigated the endocrinological results of 56 patients, who were surgically treated because of a GH-producing pituitary adenoma, by different criteria. Twelve of our patients had had additional medical treatment after surgery, two received radiotherapy. At a mean follow-up of 34 months after surgery 66% of patients had a basal GH < 5 ng/ml, 64% had a GH in the OGTT < 2 ng/ml and 73% had normalization of IGF-1. The combined criteria of OGTT < 2 ng/ml and IGF-1 normalization have been fulfilled in 59% of patients. None of these latter patients developed a clinical recurrence during the follow-up period. An optimal result (endocrinological cure, no permanent surgical complications and intact pituitary function) was achieved in 43% of patients. Although surgery was responsible for 19 new pituitary axis deficiencies (7 corticotropic axis, 8 thyrotropic axis and gonadotropic axis), 22 partial deficiencies improved to normalization after surgery (respectively 6, 3, and 13). Pre-operatively 55% of patients had no pituitary deficiency, after surgery this was 61%, leaving a net positive result of 6% less pituitary deficiencies. The authors conclude that normalization of IGF-1 combined with an OGTT < 2 ng/ml are adequate criteria for the definition of cure of acromegaly. However, the authors propose to include post-treatment hypopituitarism as an additional criterion by which treatment of acromegaly should be evaluated.