Preliminary data on biochemical remission of acromegaly after somatostatin analogs withdrawal

OBJECTIVE: It is still unknown whether prolonged treatment with somatostatin analogs (SSTa) may cause a long-lasting disease remission in GH-secreting adenomas after drug discontinuation. The aim of the present study was to investigate the evolution of GH/IGF-I secretion and tumor mass after SSTa withdrawal in patients affected by acromegaly. PATIENTS AND DESIGN: A total of 27 patients with acromegaly (12 de novo and 15 previously operated) were treated with SSTa for a median period of 48 months and considered optimally controlled in hormonal and neuroradiological terms. None of them were previously irradiated. METHODS: Basal GH, post-glucose GH nadir, IGF-I, clinical signs/symptoms, and metabolic parameters were evaluated after 12-16 weeks from drug withdrawal. Only patients who met the current criteria for disease remission remained in drug suspension being periodically re-evaluated for biochemical/clinical data and neuroradiological imaging. RESULTS: After 12-16 weeks withdrawal, 15 of the 27 patients had disease relapse and restarted SSTa, while 12 were considered 'in disease remission' (44% of total). Glucose metabolism improved in both euglycemic and diabetic patients after short-term SSTa discontinuation. Only one of the ten patients who reached 24 weeks withdrawal showed biochemical disease recurrence. On the whole, five of the patients still in remission after 6 months have already prolonged the follow-up over 12 months (median: 24 months), without clinical and biochemical/neuroradiological evidence of disease recurrence. CONCLUSIONS: These preliminary data indicate a successful withdrawal of SSTa at least in a subset of well-responsive patients with acromegaly and challenge the previously held concept that medical therapy is always a lifelong requirement.