The therapeutic response of somatotropinomas according to the T2-weighted signal intensity on the MRI
Background and aim. Identifying the predictive factors of tumoral and hormonal answer of somatotropinomas to the medical treatment with somatostatin analogs represent an important element for treatment management. The aim of this study was to assess the therapeutic answer of the somatotropinomas according to the T2-weighted signal intensity on the MRI.
Methods. We included 31 acromegalic patients, mean age 51.35 ± 10.37 years, who underwent surgery. The patients were divided according to the T2-weighted MRI signal intensity - hypointense, hyperintense and isointense - of the GH-secreting pituitary adenoma and were evaluated after surgery, 3, 6 and 12 months with somatostatin analogs therapy.
Results. 16 (51.61%) somatropinomas were hypointense, 9 (29.03%) were hyperintense and 6 (19.35%) were isointense. The median IGF-1 and GH level decreased significantly in macroadenomas (p<0.001, p<0.001, respectively), whereas GH decreased significantly only in microadenomas (p=0.010). A significant statistical correlation was found between IGF-1 or GH levels and tumor volume before surgery (Spearman=0.38, p<0.001; Spearman=0.64, p<0.001, respectively) and after surgery (Spearman=0.61, p=0.001; Spearman=0.74, p<0.001). The percentage of optimally controlled patients increased from 12.9% after surgery, to 28.57% after 12 months with somatostatin analogs. The highest percentage of optimally controlled patients with somatostatin analogs treatment was in hypointense somatotropinomas (50%).
Conclusion. The T2-weighted MRI signal intensity classifies the somatotropinomas into groups with certain evolutive and medical treatment response particularities, of which we found that the hypointense somatotropinomas have a better therapeutic response after surgery and after long-term treatment with somatostatin analogs.