Cell proliferation and outcome of GH-secreting pituitary adenomas
L De Marinis1, A Bianchi1, L Tilaro1, F Doglietto2, F Veltri1, GV Vellone3, F Lugli1, A Fusco1, V Cimino1, A Pontecorvi1 & L Lauriola1
In order to investigate the correlations between immunohistochemical picture with proliferative index (Ki-67), the clinical course and outcome of GH-secreting pituitary adenomas not cured by neurosurgery, we studied 41 consecutive acromegalic patients (M 12, F 29; aged 43±10.8 yr) previously undergone neurosurgical resection of adenoma. Two patients underwent neurosurgical intervention at least twice. Post-surgical follow-up ranged from 6 to 36 months and all patients received medical treatment with somatostatin analogs because relapse or persistence of disease. Ki-67 determination was effectuated on 43 surgical specimens. Patients were divided in 2 groups according to Ki-67 value of the surgical specimen (≤1% or >1%).
The first group (Ki-67 ≤1%) was composed by 23 patients (M8; F15; aged 45±2 yrs.; 20 Macro- and 3 microadenomas), one of which underwent two neurosurgical resections. The mean value of IGF-I before surgery was 634±52 ng/ml, while during follow-up was 280±31 ng/ml. At last neuroradiological control, 5 patients (21.7%) showed residue/relapse of desease, while 18 (78.3%) of them had a negative magnetic resonance imaging (MRI). The second group (Ki-67 >1%) was composed by 19 patients (M 4; F 15; aged 41±3 yrs. 18 Macro- and 1 microadenomas), one of which underwent two neurosurgical resections. The mean value of IGF-I before surgery was 814.2±58 ng/ml, while during follow-up was 456±59 ng/ml. At last neuroradiological control 11 (61.1%) patients showed residue/relapse of desease, while 7 (38.9%) of them had a negative MRI. Our results showed that ki-67 index seems to be related to prognosis of GH-secreting adenomas in terms of both neurosurgical outcome and biochemical response to somatostatin analogs, independently from size of adenomas and age at diagnosis.