This Article Full Text Full Text (PDF) A correction has been published All Versions of this Article: 93/9/3436    most recent Author Manuscript (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Google Scholar Articles by Colao, A. Articles by Lombardi, G. PubMed PubMed Citation Articles by Colao, A. Articles by Lombardi, G. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Related Collections Neuroendocrinology and Pituitary Endocrine Oncology

Growth Hormone-Secreting Tumor Shrinkage after 3 Months of Octreotide-Long-Acting Release Therapy Predicts the Response at 12 Months

Department of Molecular and Clinical Endocrinology and Oncology, Section of Endocrinology, University "Federico II" of Naples, 80131 Naples, Italy

Address all correspondence and requests for reprints to: Annamaria Colao, M.D., Ph.D., Department of Molecular and Clinical Endocrinology and Oncology, "Federico II" University of Naples, via S. Pansini 5, 80131 Naples, Italy. E-mail: colao{at}unina.it.

Objective: The objective of the study was to evaluate whether tumor shrinkage or GH and IGF-I levels achieved after 3 months predicted tumor shrinkage after 12 months of octreotide-long-acting release (LAR) treatment.

Patients: Patients included 67 patients with de novo acromegaly (33 women, 34 men; aged 20–82 yr) receiving LAR at a dose of 20 mg every 28 d for 3 months. Final LAR dose was 10 mg every 28 d in 4, 30 mg every 28 d in 39, 20 mg every 28 d in 24 patients.

Design: The design of the study was analytical, observational, open, and retrospective.

Outcome Measures: Percent change in GH and IGF-I levels and tumor volume after 3 and 12 months of therapy was measured. Stepwise regression and receiving-operator characteristics analysis were used to calculate the optimal cutoff to predict 12 months tumor shrinkage at 12 months.

Results: The percent tumor shrinkage after 12 months was significantly correlated with GH, IGF-I, and tumor volume at 3 months and with the dose of LAR administered between 3 and 12 months. There was no correlation with gender, age, baseline GH levels and tumor volume. In a stepwise regression analysis, percent tumor shrinkage after 3 months was the best predictor of tumor shrinkage after 12 months (t = 5.92; P < 0.0001), followed by GH levels after 3 months (t = 2.86; P = 0.0056). To predict 50% or greater tumor shrinkage after 12 months, the best cutoff point of tumor shrinkage at 3 months was 22.1% [sensitivity (95% confidence interval) = 85.5% (71.2–95.4); specificity = 83.3% (65.3–94.3)], whereas that of GH levels after 3 months was 7.8 µg/liter [sensitivity = 70.3% (53.0–84.1); specificity = 93.3% (79.0–99.0)].

Conclusion: Tumor shrinkage achieved after 3 months of LAR treatment at 20 mg/28 d predicted tumor shrinkage at 12 months, provided that dosages were changed according to individual patients requirement.