Guidelines versus real life practice: the case of colonoscopy in acromegaly

Position statement on the diagnosis and management of acromegaly: The French National Diagnosis and Treatment Protocol (NDTP)

Acromegaly is a rare disease with prevalence of approximately 60 cases per million, slight female predominance and peak onset in adults in the fourth decade. Clinical diagnosis is often delayed by several years due to the slowly progressive onset of symptoms. There are multiple clinical criteria that define acromegaly: dysmorphic syndrome of insidious onset, symptoms related to the pituitary tumor (headaches, visual disorders), general signs (sweating, carpal tunnel syndrome, joint pain, etc.), complications of the disease (musculoskeletal, cardiovascular, pneumological, dental, metabolic comorbidities, thyroid nodules, colonic polyps, etc.) or sometimes clinical signs of associated prolactin hypersecretion (erectile dysfunction in men or cycle disorder in women) or concomitant mass-induced hypopituitarism (fatigue and other symptoms related to pituitary hormone deficiencies). Biological confirmation is based initially on elevated IGF-I and lack of GH suppression on oral glucose tolerance test or an elevated mean GH on repeated measurements. In confirmed cases, imaging by pituitary MRI identifies the causal tumor, to best determine management. In a minority of cases, acromegaly can be linked to a genetic predisposition, especially when it occurs at a young age or in a familial context. The first-line treatment is most often surgical removal of the somatotroph pituitary tumor, either immediately or after transient medical treatment. Medical treatments are most often proposed in patients not controlled by surgical removal. Conformal or stereotactic radiotherapy may be discussed on a case-by-case basis, especially in case of drug inefficacy or poor tolerance. Acromegaly should be managed by a multidisciplinary team, preferably within an expert center such as a reference or skill center for rare pituitary diseases.

Serum biomarkers of colonic polyps in patients with acromegaly: a meta-analysis and systematic review

PURPOSE

In the past few decades, acromegaly and colonic polyps have been associated with an increased risk of colorectal cancer. Previous studies highlighted the importance of serum biomarkers of colonic polyps in patients with acromegaly.

METHODS

We reviewed studies on serum biomarkers of colonic polyps in patients with acromegaly, published on PubMed, Embase, Cochrane Library, Medline, and Chinese databases from January 1, 1966, to May 8, 2022. Meta-analysis and systematic review were conducted using Stata MP 14.0.

RESULTS

Eight articles were included in this study. The mean (standard deviation) concentrations of serum biomarkers for acromegaly with and without colorectal polyps were extracted from these studies. Meta-analysis results showed that, compared to patients without colonic polyps, the levels of insulin-like growth factor-1 × upper limit of normal range (IGF-1 × ULN) and fasting insulin were significantly increased; while the levels of growth hormone (GH) were significantly decreased in patients with acromegaly and colonic polyps (IGF-1 × ULN: SMD 0.23; 95% CI 0.03-0.42, p < 0.05) (fasting insulin: SMD 0.95; 9 5% CI 0.11-1.8, p < 0.05) (GH: SMD - 0.25; 95% CI - 0.41 to - 0.08, p < 0.05). IGF-1 and FPG levels did not differ significantly (IGF-1: SMD -0.03; 95% CI - 0.22 to 0.17, p > 0.05) (FPG: SMD 0.14; 95% CI - 0.23 to 0.52, p > 0.05). The systematic review results suggest no significant differences in hemoglobin A1C, TSH, free thyroxine, FT4, T3, PRL, total cholesterol, HDL, LDL, fibrinogen, clathrate antigen, serum antigen 19-9, and α-fetoprotein levels, but serum Klotho levels.

CONCLUSION

We present the first meta-analysis and systematic review of serum biomarkers in patients with acromegaly or colonic polyps. The prevalence of colonic lesion polyps, is associated with higher IGF-1 × ULN levels, higher insulin levels in acromegaly. Further research is required to confirm GH and serum soluble Klotho levels as biomarkers of colonic polyps. When IGF-1 × ULN, fasting insulin levels change in patients with acromegaly, the occurrence of colonic polyps should be monitored. Early detection may reduce the possibility of developing malignant colon neoplasms.

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.

Clinical Characteristics and Associated Factors of Colonic Polyps in Acromegaly

PURPOSE

To investigate the clinical characteristics and associated factors of colonic polyps in patients with acromegaly.

METHODS

Clinical characteristics and colonoscopy findings of 86 acromegaly patients who received treatment were retrospectively reviewed, and colonoscopy findings and the correlation with growth hormone (GH)-secreting pituitary adenoma (GHPA) volume and hormonal/metabolic levels were analyzed.

RESULTS

The prevalence of colonic polyps in acromegaly patients was 40.7% and increased significantly with advanced age, especially in those ≥50 years. Multiple polyps (62.8%) and colonic polyps in the left colon (54.2%) were detected more frequently. Compared to acromegaly patients without polyps, those with polyps displayed higher insulin-like growth factor-1 × upper limit of normal (IGF-1×ULN) levels (P=0.03). IGF-1 levels and GHPA volumes in patients with polyps showed increasing trends, although the differences were not significant. GH levels were higher in patients with polyps of diameter ≤5 mm than those with polyps of diameter >5 mm (P=0.031). The univariate and multivariate logistic regression analysis revealed that GHPA volumes (OR: 1.09, 95% CI: 1.01-1.20; P=0.039) and IGF-1×ULN Q2 levels (OR: 6.51, 95% CI: 1.20-44.60; P=0.038) were independent factors for predicting the risk of colonic polyp occurrence in acromegaly patients. A nomogram was prepared to evaluate the risk of colonic polyps in acromegaly patients.

CONCLUSION

The acromegalic patients are a population with a high prevalence of colonic polyps. GHPA volumes and IGF-1×ULN levels may be predictors of colonic polyp occurrence.

Acromegaly and Colorectal Neoplasm: An Update

Acromegaly is a systemic disease caused by excessive inappropriate secretion of GH and IGF-I levels, resulting in many systemic complications, including cardiovascular, respiratory, metabolic diseases, and a possible increased risk of some neoplasias. Although many studies on acromegaly and cancer remain uncertain, most data indicate that colorectal cancer (CRC) incidence is increased in this population. The exact mechanism involved in the role of GH-IGF-I axis in CRC has not been fully explained, yet it is associated with local and circulating effects of GH and IGF-I on the colon, promoting angiogenesis, cell proliferation, risk of mutation, inhibition of tumor-suppressor genes and apoptosis, thus facilitating a tumor microenvironment. Nevertheless, population-based studies present controversial findings on CRC incidence and mortality. All worldwide guidelines and expert consensuses agree with the need for colonoscopic screening and surveillance in acromegaly, although there is no consensus regarding the best period to do this. This review aims to analyze the existing data on CRC and acromegaly, exploring its pathophysiology, epidemiological studies and their limitations, colonic polyp characteristics, overall cancer and CRC incidences and mortality, risk factors for colon cancer pathophysiology, and recommendation guideline aspects.

Pituitary tumors and the risk of other malignancies: is the relationship coincidental or causal?

Pituitary adenomas are benign neoplasms of the pituitary. The most prevalent are prolactinomas and non-functioning pituitary adenomas, followed by growth hormone- and ACTH-secreting adenomas. Most pituitary adenomas seem to be sporadic and their persistent growth is very atypical. No molecular markers predict their behavior. The occurrence of pituitary adenomas and malignancies in the same patient can be either pure coincidence or caused by shared underlying genetic susceptibility involved in tumorigenesis. Detailed family history on cancers/tumors in the first, second and third generation of family members on each side of the family has been reported in a few studies. They found an association of pituitary tumors with positive family history for breast, lung and colorectal cancer. We have reported that in about 50% of patients with pituitary adenomas, an association with positive family history for cancer has been found independent of secretory phenotype (acromegaly, prolactinoma, Cushing's disease or non-functioning pituitary adenomas). We also found earlier onset of pituitary tumors (younger age at diagnosis of pituitary tumors) in patients with a strong family history of cancer. In our recent unpublished series of 1300 patients with pituitary adenomas, 6.8% of patients were diagnosed with malignancy. The latency period between the diagnosis of pituitary adenoma and cancer was variable, and in 33% of patients, it was longer than 5 years. Besides the inherited trophic mechanisms (shared underlying genetic variants), the potential influence of shared complex epigenetic influences (environmental and behavioral factors - obesity, smoking, alcohol intake and insulin resistance) is discussed. Further studies are needed to better understand if patients with pituitary adenomas are at increased risk for cancer.

Insulin-Like Growth Factor 1 (IGF-1) Signaling in Glucose Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common aggressive carcinoma types worldwide, characterized by unfavorable curative effect and poor prognosis. Epidemiological data re-vealed that CRC risk is increased in patients with metabolic syndrome (MetS) and its serum components (e.g., hyperglycemia). High glycemic index diets, which chronically raise post-prandial blood glucose, may at least in part increase colon cancer risk via the insulin/insulin-like growth factor 1 (IGF-1) signaling pathway. However, the underlying mechanisms linking IGF-1 and MetS are still poorly understood. Hyperactivated glucose uptake and aerobic glycolysis (the Warburg effect) are considered as a one of six hallmarks of cancer, including CRC. However, the role of insulin/IGF-1 signaling during the acquisition of the Warburg metabolic phenotypes by CRC cells is still poorly understood. It most likely results from the interaction of multiple processes, directly or indirectly regulated by IGF-1, such as activation of PI3K/Akt/mTORC, and Raf/MAPK signaling pathways, activation of glucose transporters (e.g., GLUT1), activation of key glycolytic enzymes (e.g., LDHA, LDH5, HK II, and PFKFB3), aberrant expression of the oncogenes (e.g., MYC, and KRAS) and/or overexpression of signaling proteins (e.g., HIF-1, TGF-β1, PI3K, ERK, Akt, and mTOR). This review describes the role of IGF-1 in glucose metabolism in physiology and colorectal carcinogenesis, including the role of the insulin/IGF system in the Warburg effect. Furthermore, current therapeutic strategies aimed at repairing impaired glucose metabolism in CRC are indicated.

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.

THE PREVALENCE OF CANCER AND ITS RELATION TO DISEASE ACTIVITY IN PATIENTS WITH ACROMEGALY: TWO CENTERS' EXPERIENCE

OBJECTIVE

Acromegaly is characterized by increased serum concentrations of growth hormone (GH) and insulin-like growth factor 1 (IGF-1). Although animal studies have demonstrated a relationship between these hormones and cancer risk, the results of human studies evaluating cancer prevalence in acromegaly are inconsistent. We aimed to investigate the prevalence of malignant neoplasms in patients with acromegaly.

METHODS

Cancer risk was evaluated in a cohort of 280 patients (male/female: 120/160; mean age: 50.93 ± 12.07 years) with acromegaly. Patients were categorized into 2 groups according to the presence or absence of cancer. Standard incidence ratios were calculated as compared to the general population.

RESULTS

From 280 patients, cancer was diagnosed in 19 (6.8%) patients; 9 (47%) of them had thyroid cancer, which was the most common cancer type. Standard incidence ratios of all cancers were 0.8 (95% CI, 0.5-1.1) and 1.0 (95% CI, 0.8-1.3) in men and women, respectively. Compared to patients without cancer, the current age was higher in patients with cancer (59 [49-65] to 51 [42-59], P = .027). In contrast, the age at diagnosis was similar in both groups. Not only was the time to diagnosis and disease duration similar in both groups but also the basal and current GH and IGF-1 levels. The prevalence of active disease was also similar between the groups (32% to 23%, P = .394).

CONCLUSION

Our findings were not consistent with the studies suggesting that patients with acromegaly encounter an increased cancer risk. Furthermore, there were similar basal and current GH and IGF-1 levels in patients with acromegaly, both with and without cancer.

Diagnosis, treatment and follow-up of patients with acromegaly in a clinical practice setting in Spain: the ACROPRAXIS program Delphi survey

AIM

The ACROPRAXIS program aims to describe the management of acromegaly in Spain and provide guidance.

METHODS

Ninety-three endocrinologists were organized into 13 panels to discuss the practical issues in managing acromegaly. Based on the key learnings, an online Delphi survey with 62 statements was performed, so those statements achieving consensus could be used as guidance. Statements were rated on a 9-point scale (9, full agreement; consensus > 66.6% of response in the same tertile).

RESULTS

Ninety-two endocrinologists (98.8%) answered two rounds of the survey (mean age 47.6 years; 59.8% women; median 18.5 years of experience). Consensus was achieved for 49 (79%) statements.

DIAGNOSIS

The levels of insulin-like growth factor I (IGFI) is the preferred screening test. If IGFI levels 1-1.3 ULN, the test is repeated and growth hormone (GH) after oral glucose tolerance test (OGTT) is assessed. A pituitary magnetic resonance is performed after biochemical diagnosis.

TREATMENT

Surgery is the first treatment choice for patients with microadenoma or macroadenoma with/without optical pathway compression. Pre-surgical somatostatin analogues (SSA) are indicated when surgery is delayed and/or to reduce anaesthesia-associated risks. After unsuccessful surgery, reintervention is performed if the residual tumor is resectable, while if non-resectable, SSA are administered. Follow-up First biochemical and clinical controls are performed 1-3 months after surgery. Disease remission is considered if random GH levels are < 1 µg/L or OGTT is < 1 or ≤ 0.4 µg/L, depending on the assay's sensitivity.

CONCLUSION

Current clinical management for acromegaly is homogeneous across Spain and generally follows clinical guidelines.

Systemic Complications of Acromegaly and the Impact of the Current Treatment Landscape: An Update

Acromegaly is a chronic systemic disease with many complications and is associated with increased mortality when not adequately treated. Substantial advances in acromegaly treatment, as well as in the treatment of many of its complications, mainly diabetes mellitus, heart failure, and arterial hypertension, were achieved in the last decades. These developments allowed change in both prevalence and severity of some acromegaly complications and furthermore resulted in a reduction of mortality. Currently, mortality seems to be similar to the general population in adequately treated patients with acromegaly. In this review, we update the knowledge in complications of acromegaly and detail the effects of different acromegaly treatment options on these complications. Incidence of mortality, its correlation with GH (cumulative exposure vs last value), and IGF-I levels and the shift in the main cause of mortality in patients with acromegaly are also addressed.