Association of hypothyroidism with survival in pancreatic cancer: retrospective cohort study

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive tumours, with a 5-year survival rate of approximately 8 per cent. This is mostly due to the delay in early diagnosis and to tumour resistance against treatments, despite considerable recent effort in both preclinical and clinical research. New studies are needed to identify potential risk factors of progression and incidence of PDAC. Thyroid disorders are a common public health problem worldwide. The most common type of thyroid disorder is hypothyroidism, which is characterized by insufficient levels of thyroxine (T4), along with elevated levels of thyroid-stimulating hormone (TSH). Levothyroxine replacement therapy is the first-line treatment for hypothyroidism. Thyroid hormones influence the growth and homeostasis of gastrointestinal organs through the binding to receptors in the epithelium. They regulate some cellular processes such as proliferation, differentiation, apoptosis and metabolism, and some studies suggest their role in cancer progression. Several clinical studies have demonstrated that hypothyroidism could inhibit cancer cell proliferation, but data on the potential association between hypothyroidism and survival of PDAC patients are lacking. The aim of this study was to examine the prevalence of hypothyroidism among patients with PDAC and assess its association with overall survival.