Magnetic resonance imaging as a predictor of response to somatostatin analogs in acromegaly after surgical failure.
BACKGROUND
Transsphenoidal surgery is considered first-line therapy for acromegaly; however, there is often a need for adjunctive therapy. Somatostatin analogs (SSA) have greatly improved the effectiveness of medical treatment, but one third of patients are resistant.


OBJECTIVE
The aim was to evaluate whether magnetic resonance imaging (MRI) signal could predict long-term response to SSA in patients with active acromegaly after neurosurgery.


METHODS
Sixty-two patients who were active acromegalic after surgery were included in this retrospective study. Remaining pituitary tumor was classified as hyper-, iso-, or hypointense by evaluating T2-weighted MRI signal. Treatment with SSA at maximal effective doses was prescribed and evaluated at 6 and 12 months by monitoring IGF-I, GH, and T2 MRI.


RESULTS
Complete response to SSA treatment (defined as normal IGF-I) at 6 months was observed in 30%, partial response (defined as IGF-I between 2 and 3 sd score) in 15%, and no response in 55% of patients. At 12 months, 28, 20, and 52% were observed, respectively. MRI signal was hypointense in 40%, hyperintense in 48%, and isointense in 12%. At 6 months, complete response to SSA was observed in 71% of cases having hypointense MRI signal and in 20% of hyperintense (P = 0.04). At 12 months, 62% of hypointense remained well controlled, whereas in the hyperintense group, good, partial, or no response results did not change from that observed at 6 months (P = 0.04).


CONCLUSIONS
In active acromegalic patients after surgery, a hypointense T2-weighted MRI signal is associated with a better response to SSA treatment at 6 and 12 months.
Puig-Domingo
Manel
M
Endocrinology Department, Hospital Clinic, University of Barcelona, Barcelona, Spain. mpuigd@gmail.com
Resmini
Eugenia
E
Gomez-Anson
Beatriz
B
Nicolau
Joana
J
Mora
Mireia
M
Palomera
Elisabet
E
Martí
Camelia
C
Halperin
Irene
I
Webb
Susan M
SM
D000172:Acromegaly / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D000328:Adult; D016009:Chi-Square Distribution; D005260:Female; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007016:Hypophysectomy; D015592:Immunoradiometric Assay; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013004:Somatostatin / Q000031:analogs & derivatives / Q000627:therapeutic use*; D018709:Statistics, Nonparametric; D016896:Treatment Outcome
D019382:Human Growth Hormone; D013004:Somatostatin; D007334:Insulin-Like Growth Factor I