Increased prevalence of colorectal polyp in acromegaly patients: a case-control study

Growth hormone and gastrointestinal malignancy: An intriguing link

Growth hormone (GH) excess is associated with several systemic complications, one of which is the increased risk of neoplastic processes particularly of the gastrointestinal (GI) tract. Among the GI neoplasms, the most reported association is with benign and malignant neoplasms of the colon. In the majority of published literature, an increased incidence of GI neoplasms, both colonic adenomas as well as colorectal carcinoma is reported. However, the studies on colon cancer-specific mortality rate are conflicting with recent studies reporting similar cancer-specific mortality rates in comparison to controls. Many studies have reported an association of colorectal neoplasms with GH levels. Pathogenic mechanisms put forward to explain this association of GH excess and GI neoplasms primarily involve the increased GH-insulin-like growth factor 1 (IGF-1) signaling. Both GH and IGF-1 have proliferative, anti-apoptotic, and angiogenic effects on the systemic tissues leading to cellular proliferation. Other contributing factors to the increased risk of GI neoplasms include slow intestinal transit with a redundant large bowel, altered bile acids, deranged local immune response, shared genetic susceptibility factors and hyperinsulinemia. In view of the increased risk association, most guidelines for the care of acromegaly patients recommend an initial screening colonoscopy. Recommendations for further follow-up colonoscopy differ but broadly, the guidelines agree that it depends on the findings at first colonoscopy and state of remission of GH excess. Regarding the concern about the risk of colorectal cancers in patients receiving recombinant GH therapy, most cohort studies do not show an increased risk.

Increased risk of preneoplastic colonic lesions and colorectal carcinoma in acromegaly: multicenter case-control study

PURPOSE

Current international guidelines recommend colonoscopy in patients with acromegaly at the time of diagnosis, even though the risk of developing colorectal neoplasm is still controversial. The main objective of this Argentine multicenter study was to analyze through screening colonoscopy the presence of advanced neoplastic lesions considered as precancerous, in patients with acromegaly compared to a control group.

METHODS

This is a case-control retrospective study. Full length colonoscopy of 70 acromegalic patients and 128 control subjects were studied. Polyps were classified into non pre-cancerous lesions and advance neoplastic lesions which included advanced adenomas (preneoplastic) and colorectal carcinomas.

RESULTS

Thirty three out of 70 acromegalic patients and 32 out of 128 subjects controls presented polyps in the colonoscopy [47.1% vs 25%, p = 0.002, OR 2.68]. Non precancerous polyps were found in 11 (15.7%) and 23 (17.9%) (p = 0.690), while advanced neoplastic lesions were found in 22 (31.4%) and 9 (7.0%) (p = 0,0001 - OR: 6.06) patients and controls respectively. Advanced adenomas and colorectal carcinomas were found in 18 (27.3%) and 9 (7.0%) (p = 0,0006-OR: 4,57), and 4 (5.7%) and 0 (0.0%) p = 0.0063) of patients and controls respectively. The presence of insulin resistance was the only statistically significant associated factor among acromegalic patients with and without colonic polyps.

CONCLUSIONS

Our findings show an increased risk of preneoplastic colonic lesions and colorectal carcinoma in patients with chronic and sustained GH excess compared to a control group. This supports the recommendation to perform screening colonoscopy at diagnosis of acromegaly.

Constipation in adults

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Prevalence of colonic polyp and its predictors in patients with acromegaly

BACKGROUND

There are conflicting data regarding the prevalence of colorectal polyp in patients with acromegaly.

SUBJECTS AND METHODS

Consecutive forty-seven acromegalic patients (21 men, 26 women), with a mean age of (40 ± 12 years) attending endocrinology outpatient department underwent full colonoscopy. All the patients underwent clinical and biochemical evaluation (glucose suppressed growth hormone (GH), Insulin-like growth factor-1 [IGF-1], fasting insulin, and glucose). The control group (n = 120) for colonoscopy was adult subjects undergoing evaluation for symptoms of irritable bowel syndrome. Clinical and biochemical parameters in acromegalic patients with colonic polyp were compared to those without a polyp.

RESULTS

Patients with acromegaly had significantly higher prevalence of colonic polyp as compared to control subjects (10.6% vs. 0.8%). None of the patients with polyp had skin tags. There was no significant difference between subjects with and without colonic polyp in duration of illness, basal, and glucose-suppressed GH and most recent IGF-1. Fasting blood sugar was significantly higher (P < 0.05) in adenoma group after adjusting for age, body mass index (BMI), and insulin levels. Patients in adenoma group showed a trend toward male gender and younger age as compared to those without adenoma.

CONCLUSIONS

Subjects with acromegaly as compared to control have a higher prevalence of colonic polyps. There was no association of polyps seen with age, BMI, skin tags, homeostasis model assessment of insulin resistance index, duration of disease, and basal and glucose-suppressed GH and IGF-1 levels. There were no specific predictive factors detected. Screening full colonoscopy is recommended in all cases with acromegaly.