Cancer prevalence in patients with acromegaly: data from the acromegaly registry of the Moscow Region

Background: The incidence of cancer in acromegaly varies substantially, ranging from 6.8% to 21.3%. Population-based studies have revealed differences both in the tumor types and in the risk factors for cancer development in acromegaly. Aim: To assess the frequency and structure of malignancies in patients with acromegaly from a single region of the Russian Federation and to identify possible clinical and biochemical predictors of cancer risk in these patients. Methods: A retrospective observational single-cohort study was performed. Data from the acromegaly registry of the Moscow Region as of December 1, 2025, were analyzed. The frequency and structure of malignancies were studied in the cohort of acromegaly patients. Clinical and biochemical characteristics, features of acromegaly course, prevalence of comorbidities, and treatment modalities were compared between acromegaly patients with and without cancer. Results: Among 423 patients with acromegaly included in the Moscow Region registry, 75 (17.7%) had malignancies, and 7 of them had multiple primary cancers. A total of 82 malignant tumors were recorded, 4 of which were diagnosed before the onset of acromegaly symptoms. The most commonly affected sites were the thyroid (18/82, 22.0%), colon (16/82, 19.5%), breast (13/82, 15.9%), and uterus (11/82, 13.4%). Patients with cancer were older at the time of acromegaly diagnosis (mean ± SD, median [LQ; UQ]: 51.5 ± 13.9, 54 [41; 62] vs 48.0 ± 13.5, 49 [38; 58] years, p = 0.036) and at the last visit (66.7 ± 12.5, 69 [61; 75] vs 60.1 ± 13.5, 61.5 [50; 70] years, p = 0.004), and had a significantly longer time to remission of acromegaly (8.9 ± 9.2, 5 [3; 12] vs 5.6 ± 5.6, 4 [2; 7] years, p = 0.021). Growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels at both acromegaly diagnosis and the last visit did not differ between groups. In the cancer group, the frequency of primary hyperparathyroidism (10.7% vs 3.9%, p = 0.009; odds ratio (OR) 3.303, 95% confidence interval (CI) 1.300–8.392) and glucose metabolism disorders (68.9% vs 54.1%, p = 0.021; OR 1.879, 95% CI 1.097–3.219) was significantly higher. Moreover, patients with cancer had significantly higher prolactin levels at acromegaly diagnosis (6080 ± 13045, 1767 [1060; 2500] vs 2098 ± 4183, 1138 [724; 1939] mIU/L, p = 0.022), although the frequency of hyperprolactinemia did not differ (24.2% vs 22.1%, p = 0.700). Conclusion: In the Moscow Region, the most frequent cancers in acromegaly patients were those of the thyroid, colon, breast, and uterus. Risk factors for cancer in acromegaly included longer duration of active acromegaly (but not the degree of GH or IGF-1 elevation), as well as the presence of glucose metabolism disorders and primary hyperparathyroidism.