The Clinical Relevance of Hypothyroidism in Patients with Solid Non-Thyroid Cancer: A Tantalizing Conundrum

Abstract

Hypothyroidism in patients with solid non-thyroid cancer is a tantalizing entity, integrating an intriguing thyroid hormones (THs)–cancer association with the complexity of hypothyroidism itself. The present narrative review provides a comprehensive overview of the clinical relevance of hypothyroidism in solid non-thyroid cancer. Hypothyroidism in patients with solid non-thyroid cancer is reminiscent of hypothyroidism in the general population, yet also poses distinct challenges due to the dual role of THs in cancer: promoting versus inhibitory. Close collaboration between oncologists and endocrinologists will enable the prompt and personalized diagnosis and treatment of hypothyroidism in patients with solid non-thyroid cancer. Clinical data indicate that hypothyroidism is a predictor of a decreased or increased risk of solid non-thyroid cancer and is a prognostic factor of favorable or unfavorable prognosis in solid non-thyroid cancer. However, the impact of hypothyroidism with respect to the risk and/or prognosis of solid non-thyroid cancer is not a consistent finding. To harness hypothyroidism, or THs replacement, as a personalized anticancer strategy for solid non-thyroid cancer, four prerequisites need to be fulfilled, namely: (i) deciphering the dual THs actions in cancer; (ii) identifying interventions in THs status and developing agents that block tumor-promoting THs actions and/or mimic anticancer THs actions; (iii) appropriate patient selection; and (iv) counteracting current methodological limitations.

Relationship between TSH and free thyroxine in outpatient cancer patient population

“…Many patients with a cancer diagnosis present with new or chronic thyroid issues [10,11]. Correspondingly, clinical and sub-clinical hypothyroidism or hyperthyroidism has been implicated in various common cancers including prostate cancer, lung cancer, gastrointestinal cancers, and breast cancer [12][13][14]; however, some of these cases of thyroid malfunction might be incidentally identi ed as thyroid disorders due to a result of their cancer status or treatment [15]. Nevertheless, underestimated hypothyroidism and hyperthyroidism may pose a problem to oncologists treating patients with symptoms related to cancer pathogenesis and treatment, which may result in reducing medication doses unnecessarily or putting treatment temporarily on hold.…”

Disorders in connections of the hypothalamic-pituitarygonadal axis in rats with Guerin’s carcinoma against the background of induced hypothyroidism

“…Our study showed that the change in the level of GnRH in the hypothalamus in rats of the reference groups had no gender specificity: it decreased in the animals of both sexes against the background of hypothyroidism, while it increased during the growth of Guerin's carcinoma. However, it is known that the combination of two pathologies can affect different pathways of regulation that is why the presence of comorbid pathology complicates and modifies the course of the primary disease [19]. In the main group, the gender differences were revealed in the direction of changes in the level of GnRH of the hypothalamus: in the females, induced hypothyroidism inhibited the increase in volumes, and the level of GnRH in the hypothalamus increased, similar to the processes in reference group No.…”

Relationship between TSH and Free Thyroxine in Outpatient Cancer Patient Population

“…Many patients with a cancer diagnosis present with new or chronic thyroid issues [10,11]. Correspondingly, clinical and sub-clinical hypothyroidism or hyperthyroidism has been implicated in various common cancers including prostate cancer, lung cancer, gastrointestinal cancers, and breast cancer [12][13][14]; however, some of these cases of thyroid malfunction might be incidentally identi ed as thyroid disorders due to a result of their cancer status or treatment [15]. Nevertheless, underestimated hypothyroidism and hyperthyroidism may pose a problem to oncologists treating patients with symptoms related to cancer pathogenesis and treatment, which may result in reducing medication doses unnecessarily or putting treatment temporarily on hold.…”