Partial surgical removal of growth hormone-secreting pituitary tumors enhances the response to somatostatin analogs in acromegaly.
BACKGROUND
Surgery is a cornerstone in the treatment of acromegaly, but its efficacy in large, invasive tumors is scant.


OBJECTIVE
The objective of this study was to investigate whether partial surgical removal of GH-secreting pituitary tumors enhances the response rate to somatostatin analogs (SSA; sc octreotide, slow-release octreotide, and lanreotide).


METHODS
This was a multicenter, open, retrospective study.


METHODS
The study was performed at university hospitals.


METHODS
Eighty-six patients (42 women and 44 men; age, 42 +/- 14 yr) with acromegaly were studied.


METHODS
Patients underwent two courses of octreotide, lanreotide, or slow-release octreotide treatments before and after surgery of at least 6 months.


METHODS
The main outcome measure was normal IGF-I levels for age.


RESULTS
Presurgical SSA treatment significantly decreased GH and IGF-I levels in all patients. GH levels were less than 2.5 microg/liter in 12 patients (14%); IGF-I levels normalized in nine (10%). After surgery, GH and IGF-I levels further decreased in all patients; tumor removal was greater than 75% in 50 (58%), 50.1-75% in 21 (24%), 25.1-50% in 10 (12%), and less than 25% in five patients (6%). Preoperatively, pituitary function was impaired in 12 patients (14%). Postsurgical SSA treatment lowered GH levels to less than 2.5 microg/liter in 49 (56%) and normalized IGF-I levels in 48 patients (55%). The success rate was significantly increased compared with that before surgery (P < 0.0001). GH (r = -0.48; P < 0.0001) and IGF-I levels (r = -0.38; P = 0.0003) after postsurgery SSA treatment correlated with the amount of tumor surgically removed. After surgery, pituitary function was impaired in 28 patients (32.6%) and was improved in 12 patients (13.9%). The cumulative prevalence of pituitary deficiency did not change during the study (normal function from 40 to 42%; deficiency from 60 to 58%).


CONCLUSIONS
Surgical tumor removal (>75%) enhances the response to SSAs without impairing pituitary function. Our data indicate that surgical debulking has a significant place in the treatment algorithm of acromegaly.
Colao
Annamaria
A
Department of Molecular and Clinical Endocrinology and Oncology, Federico II University of Naples, via S. Pansini 5, 80131 Naples, Italy. colao@unina.it
Attanasio
Roberto
R
Pivonello
Rosario
R
Cappabianca
Paolo
P
Cavallo
Luigi M
LM
Lasio
Giovanni
G
Lodrini
Alessandro
A
Lombardi
Gaetano
G
Cozzi
Renato
R
D000172:Acromegaly / Q000188:drug therapy / Q000601:surgery / Q000628:therapy*; D000236:Adenoma / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D000328:Adult; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D015331:Cohort Studies; D003131:Combined Modality Therapy; D005260:Female; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D007016:Hypophysectomy; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015282:Octreotide / Q000627:therapeutic use; D010456:Peptides, Cyclic / Q000627:therapeutic use; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D016896:Treatment Outcome
D018931:Antineoplastic Agents, Hormonal; D010456:Peptides, Cyclic; C060347:lanreotide; D019382:Human Growth Hormone; D013004:Somatostatin; D007334:Insulin-Like Growth Factor I; D015282:Octreotide