The association of fasting insulin concentrations and colonic neoplasms in acromegaly: a colonoscopy-based study in 210 patients.
BACKGROUND
Hyperinsulinemia is associated with colon carcinoma in the general population. PATIENTS with acromegaly are considered to be at risk for developing colonic lesions and typically have hyperinsulinemia.


OBJECTIVE
Our objective was to evaluate the role of fasting insulin levels on the prevalence of colonic adenomatous polyps or adenocarcinoma in acromegaly.


METHODS
This is an analytical, observational, prospective study.


METHODS
A total of 210 patients (111 women, 99 men, age 20-82 yr) undergoing complete colonoscopy at diagnosis of acromegaly were included in this study.


RESULTS
Colonic lesions were found in 81 patients (38.6%), and consisted of hyperplastic polyps in 33 (15.7%), adenomatous polyps in 42 (20.0%), and adenocarcinoma in six patients (2.8%). Polyps were single in 22 cases (27.1%). Fasting insulin levels were significantly lower in patients without lesions (16.0 +/- 7.5 mU/liter) than in patients with hyperplastic polyps (22.4 +/- 8.8 mU/liter; P < 0.01), adenomatous polyps (38.0 +/- 15.9 mU/liter; P < 0.0001), and adenocarcinoma (59.0 +/- 30.6 mU/liter; P < 0.0001). Fasting insulin levels were also lower in patients with hyperplastic polyps than in those with adenomatous polyps (P < 0.01). The odds ratio for harboring colonic adenomas was 14.8 (95% confidence interval 4.4-51.2; P < 0.0001) and 8.6 times higher (95% confidence interval 2.8-29.0; P < 0.0001) in patients with fasting insulin levels in the upper tertile [>/=27.1 mIU/liter (n = 28)] compared with the lower [</=12.1 mIU/liter (n = 40)] and middle tertiles [>12.1 to <27.1 mIU/liter (n = 74)], respectively.


CONCLUSIONS
An increase in fasting insulin levels is associated with an 8.6- to 14.8-fold increased risk of presenting with colonic adenomas in acromegaly.
Colao
Annamaria
A
Department of Molecular, Clinical Endocrinology and Oncology, Section of Endocrinilogy, University Federico II of Naples, via S. Pansini 5, 80131 Naples, Italy. colao@unina.it
Pivonello
Rosario
R
Auriemma
Renata S
RS
Galdiero
Mariano
M
Ferone
Diego
D
Minuto
Francesco
F
Marzullo
Paolo
P
Lombardi
Gaetano
G
D000172:Acromegaly / Q000097:blood / Q000453:epidemiology*; D000230:Adenocarcinoma / Q000097:blood / Q000453:epidemiology* / Q000473:pathology; D018256:Adenomatous Polyps / Q000097:blood / Q000453:epidemiology* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000097:blood / Q000453:epidemiology* / Q000473:pathology; D003113:Colonoscopy; D005215:Fasting; D005260:Female; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D006965:Hyperplasia; D007328:Insulin / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors
D007328:Insulin; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I