Cancer Incidence in Patients With Acromegaly: A Cohort Study and Meta-Analysis of the Literature

Abstract

Abstract Context Acromegaly has been associated with increased risk of cancer morbidity and mortality, but research findings remain conflicting and population-based data are scarce. We therefore examined whether patients with acromegaly are at higher risk of cancer. Design A nationwide cohort study (1978 to 2010) including 529 acromegaly cases was performed. Incident cancer diagnoses and mortality were compared with national rates estimating standardized incidence ratios (SIRs). A meta-analysis of cancer SIRs from 23 studies (including the present one) was performed. Results The cohort study identified 81 cases of cancer after exclusion of cases diagnosed within the first year [SIR 1.1; 95% confidence interval (CI), 0.9 to 1.4]. SIRs were 1.4 (95% CI, 0.7 to 2.6) for colorectal cancer, 1.1 (95% CI, 0.5 to 2.1) for breast cancer, and 1.4 (95% CI, 0.6 to 2.6) for prostate cancer. Whereas overall mortality was elevated in acromegaly (SIR 1.3; 95% CI, 1.1 to 1.6), cancer-specific mortality was not. The meta-analysis yielded an SIR of overall cancer of 1.5 (95% CI, 1.2 to 1.8). SIRs were elevated for colorectal cancer, 2.6 (95% CI, 1.7 to 4.0); thyroid cancer, 9.2 (95% CI, 4.2 to 19.9); breast cancer, 1.6 (1.1 to 2.3); gastric cancer, 2.0 (95% CI, 1.4 to 2.9); and urinary tract cancer, 1.5 (95% CI, 1.0 to 2.3). In general, cancer SIR was higher in single-center studies and in studies with <10 cancer cases. Conclusions Cancer incidence rates were slightly elevated in patients with acromegaly in our study, and this finding was supported by the meta-analysis of 23 studies, although it also suggested the presence of selection bias in some earlier studies.