The common consensus criteria have high predictive values for long-term postoperative acromegaly remission.

OBJECTIVE: The aim of this work was to retrospectively study the long-term reliability of the common consensus endocrinological criteria for the assessment of postoperative remission of acromegaly. PATIENTS AND METHODS: In 96 consecutive patients, surgical remission of acromegaly following transsphenoidal surgery was considered to be present when, without adjuvant treatment, 3 months postoperatively there was no clinical evidence of persisting disease, and, according to the common consensus criteria for acromegaly remission, GH was suppressed to < 1 µg/l during the oral glucose tolerance test (OGTT) and insulin like growth factor-1 (IGF-1) was within normal limits. The results of the second postoperative week, 3 months postoperative, and the most recent follow-up OGTT and IGF-1 measurements were used to calculate the positive and negative predictive values of the following endocrinological criteria of acromegaly remission: the common consensus criteria for acromegaly remission, GH suppression to < 1 µg/l during OGTT and IGF-1 within normal limits. Sensitive IRMA (≤ 0.3 µg/l) and RIA (≤ 32 µg/l) assays for GH and IGF-1 were used. RESULTS: The surgical remission rate of acromegaly was 72.9%. At a median follow-up of 5.06 years, the recurrence rate of acromegaly was 2.08%. Overall, the common consensus criteria for acromegaly remission were the most reliable tests, with the following positive and negative predictive values at 2 weeks postoperatively, 3 months postoperatively and at the most recent follow-up: 68%, 100% and 100%, and 98%, 100% and 100%, respectively. The negative likelihood ratio confirmed that the test qualities of the common consensus criteria for acromegaly remission were superior to the other tests. CONCLUSIONS: The common consensus criteria were the most reliable tests for the diagnosis of postoperative acromegaly remission. The positive and negative predictive values of the common consensus criteria for acromegaly remission increased from the second postoperative week to 3 months postoperatively, thereafter reliably indicating the long-term results of transsphenoidal surgery.

Reliability of the oral glucose tolerance test in the early postoperative assessment of acromegaly remission.

OBJECT: The suppression of growth hormone (GH) to less than 1 microg/L during the oral glucose tolerance test (OGTT) is generally considered to be the standard for the assessment of biochemical remission of GH excess following surgery for GH-secreting pituitary adenomas. In this study the authors examine the reliability of the results of the early postoperative OGTT (epOGTT) in indicating remission or persistence of active acromegaly. METHODS: Data from the case files of 67 consecutive patients who underwent surgery for the first time for GH-secreting pituitary adenomas were reviewed retrospectively. Definitive remission of acromegaly was considered to be present if, without adjuvant therapy and at the most recent follow-up examination, GH was suppressed to less than 1 microg/L during the OGTT, the level of insulin-like growth factor-I (IGF-I) was within normal limits, and there was no clinical or magnetic resonance imaging evidence of persisting disease. The results of the epOGTT (obtained during the 2nd postoperative week) and the 3-month-postoperative OGTT (3mpOGTT) were compared with the patient's outcome at the most recent follow-up examination. A highly sensitive (< or = 0.3 microg/L) immunoradiometric assay for GH and a highly sensitive (< or = 32 microg/L) radioimmunoassay for IGF-I were used. Correct epOGTT findings were noted in 83.6% of the patients: correct normal results (definitive remission of acromegaly) in 55.2% and correct pathological results (persisting acromegaly) in 28.3% of the patients. The rate of false findings was 16.4%: false normal results in 1.5% and false pathological results in 14.9% of the patients. The rate of correct 3mpOGTT findings increased to 98.5%: correct normal results in 68.6% and correct pathological ones in 29.8% of the patients. A false (false pathological) 3pmOGTT result occurred in only one patient (1.5%). At the most recent follow-up examinations (median 3.6 years) all OGTT findings were correct: correct normal results in 70.1% and correct pathological results in 29.9% of the patients. An intact adenopituitary function was associated (p = 0.04) with the occurrence of false epOGTT findings. CONCLUSIONS: The high rate of false results, 16.4% for the epOGTT, declined significantly to 1.5% 3 months postoperatively and to 0% at the most recent follow-up examination. The OGTT appears to be more reliable at 3 months postoperatively. Unless there is obvious evidence of persisting disease following surgery for GH-secreting pituitary adenomas, adjuvant therapy should be delayed for 3 months postoperatively to avoid subjecting the patient to superfluous treatment.