Conventional pituitary irradiation is effective in normalising plasma IGF-I in patients with acromegaly.

Abstract

OBJECTIVE:

For patients in whom acromegaly persists despite pituitary surgery, conventional pituitary irradiation represents an additional treatment option. A 30-60% cure rate is described in the literature, but these studies did not utilise strict rules of remission, such as "safe" GH levels <2.5 microg/l, and age-adjusted normal IGF-I levels.

DESIGN AND METHODS:

We report the outcome of 41 patients with acromegaly who received pituitary conventional external irradiation. The median follow-up time was 12.8 years (3.7-43.4 years) post-radiotherapy.

RESULTS:

The median pre-irradiation GH level was 31.0 microg/l (7.0-210 microg/l). Information on IGF-I levels was only available for 6 patients prior to therapy. Utilising strict rules of remission, one-third (14/41) of our patients had normal biochemical parameters, i.e. "safe" GH (0.5 microg/l (range 0.2-1.6 microg/l)) and normal age-adjusted IGF-I levels (multiple of upper limit of normal range (xULN); 0.45 (0.2-1.0)) at the end of the follow-up period. An additional 9 patients achieved normal levels with adjunctive drug therapy. Furthermore, disease activity was reduced in a considerable proportion of the 18 patients who did not achieve normal biochemical levels (GH: 3.6 microg/l (1.9-15.7 microg/l); xULN of IGF-I: 1.6 (0.9-2.6)). In retrospect, remission is unlikely in patients who had a GH level greater than 52 microg/l (mean+2 s.d. of cured patients) prior to radiotherapy. In addition to the 12 patients with pre-irradiation pituitary functional deficiency, another 11 patients developed symptoms of panhypopituitarism during the 3-year period following irradiation. Within a 6-year period, partial pituitary insufficiency was observed in a further 7 patients, thus necessitating hormone substitution treatment.

CONCLUSION:

Using strict rules of remission, in our cohort we found both a normalisation of IGF-I and safe GH levels in 34% of patients treated for acromegaly with conventional irradiation therapy.

• Authors: B Gutt, C Hatzack, K Morrison, B Pöllinger, J Schopohl
• Journal: European journal of endocrinology (Eur J Endocrinol) Vol. 144 Issue 2 Pg. 109-16 (Feb 2001) ISSN: 0804-4643 [Print] England
• PMID: 11182746 (Publication Type: Journal Article)

Chemical References

• Human Growth Hormone
• Insulin-Like Growth Factor I

Topics

• Acromegaly (blood, physiopathology, radiotherapy)
• Adult
• Aged
• Cohort Studies
• Female
• Human Growth Hormone (blood)
• Humans
• Insulin-Like Growth Factor I (analysis)
• Male
• Middle Aged
• Osmolar Concentration
• Pituitary Gland (radiation effects)
• Pituitary Gland, Anterior (physiopathology)
• Reference Values
• Retrospective Studies