Endocrine Abstracts

Experimental and epidemiological studies have implicated high serum GH and IGF1 levels as potential contributors to tumor progression by both endocrine and paracrine mechanisms. It is still a matter of debate, however, if the prevalence of cancer is increased in acromegaly, as this disorder, characterized by chronic GH and IGF1 hypersecretion, is also associated with elevated IGFBP3 levels, which has proapoptotic and anti-proliferative protective effects. On the other hand, non-endocrine mechanisms and epigenetic/genetic variations may favor the development of tumors in acromegaly. Currently, most investigators agree with the idea that acromegaly is associated with a modest increased risk for some types of tumors, especially colon and thyroid, and mainly in patients with active disease. Most guidelines have suggested a colonoscopy at diagnosis of acromegaly, because colonic neoplasia has been found in up to 19.3% of acromegalic individuals younger than 40 years in comparison with 4.4% of controls. The optimal follow-up is controversial, but as a general rule, patients with polyps or persistently active disease should repeat colonoscopy after 5 years, while in those with normal exam and controlled disease, every 10 years or according to the recommendations for the general population. Case–control studies and recent meta-analysis have demonstrated a high rate of nodular goiter and thyroid cancer in acromegaly, advocating for close surveillance by thyroid ultrasonography. This is not a consensus, however, and some guidelines only recommend a thyroid ultrasound for patients with a palpable thyroid nodule. In relation to other common tumors, as breast and prostate cancer, the prevalence does not seem to be increased in acromegaly and the patients should be followed in a similar way as the normal population. Some studies, however, have found an increased cancer-related mortality with these tumors in acromegalic patients.