Clinical value of 68Ga-DOTATATE PET/CT in pituitary adenoma: a pilot study

Objective To investigate the correlation between the uptake of 68Ga-DOTATATE in pituitary adenoma and clinical parameters such as hormonal hypersecretion, and to evaluate the curative effect with 68Ga-DOTATATE imaging after octreotide therapy in patients with growth hormone-secreting adenoma (GH adenoma). Methods A total of 34 patients (15 males, 19 females) with pituitary adenoma were recruited, including 5 adrenocorticotropic hormone-secreting adenoma (ACTH adenoma), 17 GH adenoma, and 12 non-functioning adenoma (NF adenoma). In the 17 patients with GH adenoma, there were 13 patients treated by octreotide intramuscular injection 3 times with a total dose of 60 mg for 3 months. The finial diagnosis was based on histology. 68Ga-DOTATATE imaging was performed, and SUVmean, tumor volume and density index (DI) were recorded in all patients. The DI was the ratio of tumor SUVmean to tumor volume. The effective therapy was defined as more than 50% of hormonal suppression or more than 20% of tumor shrinkage. Non-parametric Mann-Whitney u test was used. Results NF adenoma showed greater tumor volume than secretory adenoma, ((9.10±7.00) cm3vs (2.92±1.60) cm3,u=43.0, P<0.05), whereas DI of secretory adenoma was higher than that of NF adenoma (7.16±4.52 vs 1.08±1.40, u=48.5, P<0.05). Additionally, DI was significantly higher(3.55±0.91 vs 1.38±0.69, u=2.0, P<0.05) in patients (n=8) with effective treatment than that in patients without effective treatment (n=5). Conclusion 68Ga-DOTATATE may be a useful probe for PET imaging in patients with pituitary adenoma, and may be valuable for predicting the therapeutic effect of somatostatin analog treatment. Key words: Pituitary neoplasms; Gallium radioisotopes; Tomography, emission-computed; Tomography, X-ray computed; DOTATATE