GH, IGF-1, and Age Are Important Contributors to Thyroid Abnormalities in Patients with Acromegaly

Prevalence of Neoplasms in Patients with Acromegaly-A Single-Center Polish Study

Background/Objectives: Neoplasms are one of the three most common causes of death in patients with acromegaly. Our study aimed to assess the incidence of benign and malignant neoplasms among patients with acromegaly and the associations between this prevalence and the disease activity, the time of acromegaly diagnosis, and the time of its first symptoms. The correlation between neoplasm occurrence and pituitary somatotropic axis hormone levels was also studied, and the prevalence of different types of neoplasms was compared between the patients with acromegaly and the Polish population. Methods: A retrospective study included a statistical analysis of the medical documentation of 230 patients with acromegaly diagnosed and treated in the Department of Endocrinology, Diabetes, and Isotope Therapy in Wrocław (Poland) between 1976 and 2023. Results: We observed 171 cases of neoplasms (144 benign and 27 malignant). All types of neoplasms and benign tumors were diagnosed more frequently, in both the short and long term, after a diagnosis of acromegaly, but, after a long time, only malignant neoplasms were more frequently diagnosed. In the cases of controlled acromegaly, all types of neoplasms and benign neoplasms were more common than in cases of cured acromegaly. The incidence of neoplasms was higher, regardless of type, in patients with active acromegaly compared to the cured disease. Malignant neoplasms of the thyroid, renal, and stomach type were more common among our subjects compared to the Polish population. Conclusions: This study confirms the association between acromegaly, as well as its activity level and the time from its diagnosis, and the prevalence of neoplasms.

Incidence and risk factors of cancers in acromegaly: a Chinese single-center retrospective study

PURPOSE

To evaluate the incidence of malignancies in acromegaly and to identify risk factors for newly-diagnostic cancers, especially the excessive growth hormone (GH) and insulin-like growth factor-1 (IGF-1).

METHODS

A retrospective cohort including 1738 consecutive hospitalized patients with acromegaly in a single referral center between 2012 and 2020 (mean follow-up 4.3 years). A gender- and age-matched case-control study (280 patients from the cohort) was performed for risk factor analysis.

RESULTS

One hundred thirteen malignancies (67 diagnosed after acromegaly) were observed. The overall newly-diagnostic cancer risk of acromegaly was higher than the general population (standardized incidence ratio (SIR) 2.81; 95% CI 2.18-3.57). The risk of thyroid cancer (n = 33, SIR 21.42; 95% CI 13.74-30.08) and colorectal cancer (n = 8, SIR 3.17; 95% CI 1.37-6.25) was elevated. In the overall cohort, IGF-1 (ULN: 1.27 vs. 0.94, p = 0.057), GH (1.30 vs. 1.00 ng/ml, p = 0.12), and disease-controlled rate (34.9% vs. 45.9%, p = 0.203) at the last visit did not reach significance between patients with and without post-diagnostic cancer. In the case-control study, GH (1.80 vs. 0.90 ng/ml, p = 0.018) and IGF-1 (ULN: 1.27 vs. 0.91, p = 0.003) at the last visit were higher in patients with post-diagnostic cancers, with a lower disease-controlled rate. Elder age was a risk factor for cancer. Other metabolic comorbidities and the size of pituitary tumors were similar.

CONCLUSION

The risk of malignancies, especially thyroid cancer, was increased in patients with acromegaly in our center. More cancer screening should be considered when managing acromegaly, especially in patients with higher posttreatment GH and IGF-1.

The Effect and Potential Mechanism Analysis of Growth Hormone-Secreting Pituitary Adenomas on Thyroid Function

OBJECTIVE

Current studies on the effect of high growth hormone (GH)/insulin-like growth factor (IGF)-1 on thyroid function are inconsistent. The aim was to explore the effect and potential mechanism of high GH/IGF-1 on thyroid function by analyzing the changes of thyroid function in patients with growth hormone-secreting pituitary adenoma (GHPA).

METHODS

This was a retrospective cross-sectional study. Demographic and clinical data of 351 patients with GHPA who were first admitted to Beijing Tiantan Hospital, Capital Medical University, from 2015 to 2022 were collected to analyze the relationship between high GH/IGF-1 levels and thyroid function.

RESULTS

GH was negatively correlated with total thyroxine (TT4), free thyroxine (FT4), and thyroid-stimulating hormone (TSH). IGF-1 was positively correlated with total triiodothyronine (TT3), free triiodothyronine (FT3), and FT4 and negatively correlated with TSH. Insulin-like growth factor-binding protein (IGFBP)-3 was positively correlated with TT3, FT3, and FT3:FT4 ratio. The FT3, TT3, TSH, and FT3:FT4 ratio of patients with GHPA and diabetes mellitus (DM) were significantly lower than those with GHPA but without DM. With the increase of tumor volume, thyroid function gradually decreased. GH and IGF-1 were correlated negatively with age in patients with GHPA.

CONCLUSION

The study emphasized the complex interaction between the GH and the thyroid axes in patients with GHPA and highlighted the potential effect of glycemic status and tumor volume on thyroid function.

Dual Characters of GH-IGF1 Signaling Pathways in Radiotherapy and Post-radiotherapy Repair of Cancers

Radiotherapy remains one of the most important cancer treatment modalities. In the course of radiotherapy for tumor treatment, the incidental irradiation of adjacent tissues could not be completely avoided. DNA damage is one of the main factors of cell death caused by ionizing radiation, including single-strand (SSBs) and double-strand breaks (DSBs). The growth hormone-Insulin-like growth factor 1 (GH-IGF1) axis plays numerous roles in various systems by promoting cell proliferation and inhibiting apoptosis, supporting its effects in inducing the development of multiple cancers. Meanwhile, the GH-IGF1 signaling involved in DNA damage response (DDR) and DNA damage repair determines the radio-resistance of cancer cells subjected to radiotherapy and repair of adjacent tissues damaged by radiotherapy. In the present review, we firstly summarized the studies on GH-IGF1 signaling in the development of cancers. Then we discussed the adverse effect of GH-IGF1 signaling in radiotherapy to cancer cells and the favorable impact of GH-IGF1 signaling on radiation damage repair to adjacent tissues after irradiation. This review further summarized recent advances on research into the molecular mechanism of GH-IGF1 signaling pathway in these effects, expecting to specify the dual characters of GH-IGF1 signaling pathways in radiotherapy and post-radiotherapy repair of cancers, subsequently providing theoretical basis of their roles in increasing radiation sensitivity during cancer radiotherapy and repairing damage after radiotherapy.

Central Hypothyroidism Related to Pituitary Adenomas: Low Incidence of Central Hypothyroidism in Patients With Acromegaly

CONTEXT

The most frequent cause of central hypothyroidism (CeH) is pituitary adenomas, but the mechanisms remain unclear.

OBJECTIVE

We investigated serum thyroid levels and GH/IGF-1 in central hypothyroidism in untreated patients with pituitary nonfunctioning and GH-secreting adenomas.

DESIGN

This was a retrospective cross-sectional study of cases collected from Gunma University and Toranomon Hospitals between 2007 and 2016.

PATIENTS

One-hundred thirty-nine cases of nonfunctioning pituitary adenoma (NFPA) and 150 cases of GH-secreting pituitary adenoma (GHPA) were analyzed.

MAIN OUTCOME MEASURES

The correlations between thyroid levels, several clinicopathological parameters, and GH/IGF-1 were examined.

RESULTS

Twenty-four percent of NFPA patients had CeH. The severity did not correlate with tumor size, age, or sex, and all cases had normal TSH levels. In contrast, only 8.7% of GHPA patients had CeH; approximately half had normal TSH levels and approximately half had low TSH levels. Serum TSH levels in GHPA patients were significantly lower and free T4 (FT4) and free T3 levels were higher than those in patients with NFPA. Furthermore, approximately one-fourth of GHPA patients had normal FT4 and low TSH levels. In addition, serum FT4 levels and serum TSH levels were positively and negatively correlated, respectively, with serum IGF-1 levels. Furthermore, IGF-1 levels in patients with GHPA decreased with age.

CONCLUSIONS

(i) NFPA patients with CeH had TSH levels within a normal range. (ii) GHPA patients had a low incidence of CeH, which may be a result of stimulated thyroid function by GH/IGF-1. (iii) We found an age-dependent decrease in serum IGF-1 levels in patients with GHPA.