Endocrine Abstracts

Background: Surgical outcomes in patients with acromegaly are highly dependent on a surgeon’s level of expertise, as the majority of patients present with macroadenomas at diagnosis.

Aim: To assess remission rates in patients with acromegaly admitted to a tertiary medical center.

Materials and methods: We included patients admitted to the neuroendocrinology and bone disease department with no previous radiation therapy or current medical therapy with SSA or pegvisomant. Suppression of GH levels less than 1.0 ng/ml was a criterion for short-term remission. Normalization of IGF-1 levels according to an age-specific reference range was a long-term remission criterion.

Results: 44 patients were included in the study: gender (32.8% m, 68.2% f), median age 47.0 [34.0;55.0], IGF-1 744.75 ng/ml [548.83;889.85], GH 9.5 ng/ml [4.94;17.07], tumor volume 832 mm3 [419,25;2532,38]. Microadenomas were identified in 8 patients (18.2%), 36 patients had macroadenomas at diagnosis (81.8%). Early postoperative remission was achieved in 35 patients (79.5%). For microadenomas the remission rate was 87.5% (n=7) and for macroadenomas it was 77.7% (n=28). Surprisingly, we did not observe differences between patients with and without early remission in age, tumor volume, histological variants and SSTR2, SSTR5 expression – this could be explained by the small sample size. Patients who achieved short-term remission had higher IGF-1 and basal GH levels: IGF-1 935,60 ng/ml [649.60;1186.00] vs 737.60 ng/ml [532.10;876.20], P=0.047, GH 36.40 ng/ml [9.61;63.30] vs 8.90 ng/ml [3.74;15.20]. Patients with no remission after surgery were prescribed with SSA. All patients were followed-up, median 19.0 months [12.5;29.0]. Long-term remission was achieved in 61.4% (27 patients), 9 patients had no remission (20.5%), 2 patients had recurrence (4.5%), 6 patients were lost to follow-up (13.6%). In line with short-term remission, patients with long-term remission had lower basal GH 8,9 ng/ml [3,76;11,9] vs 28,0 ng/ml [6,75;47,2], P=0.006 and IGF-1 674,80 ng/ml [482,5;876,2] vs 771,0 ng/ml [649,6;992,0], P=0.030. We assessed the predictive value of basal GH for long-term remission: AUC 0.811 (95%CI:0.649; 0.973). A cut-off value of 15.55 ng/ml yielded the following results: sensitivity 70.0% (34.8%;93.3%) specificity 85.7% (67.3%;96.0%), accuracy 81.6% (65.7%;92.3%), positive predictive value 63.6% (39.3%;82.5%), negative predictive value 88.9% (75.4%;95.4%). This model demonstrates poor PPV, however, good NPV shows the potential predictive use.

Conclusion: Our study demonstrates short-term and long-term remission rates comparable with literature-reported rates for experienced pituitary centers. Basal GH shows potential for prediction of long-term remission of acromegaly in the Russian population, however cohorts should be substantially increased for more accurate results.