Impact of Stress and Obesity on Cancer

Abstract

Cancer development and progression are influenced by interacting biological, metabolic, immune, and psychosocial factors. Chronic psychological stress and obesity are potentially modifiable conditions that may contribute to a tumour-promoting environment through neuroendocrine activation, metabolic dysregulation, inflammation, and impaired immune surveillance. This narrative review summarises evidence on the individual and combined roles of chronic stress and obesity in cancer initiation, progression, metastasis, therapeutic resistance, and relapse, with emphasis on immune modulation and cytokine signalling. Literature was reviewed from major electronic databases, including PubMed, Scopus, Web of Science, ScienceDirect, and Google Scholar, using search terms related to psychological stress, obesity, cancer, and immune modulation. The reviewed evidence suggests that persistent activation of the hypothalamic-pituitary-adrenal axis and sympathetic nervous system may increase circulating cortisol and catecholamines, which can influence DNA repair, angiogenesis, inflammatory signalling, and antitumour immune responses. Obesity may further contribute through adipose tissue dysfunction, insulin resistance, altered adipokine profiles, increased leptin, reduced adiponectin, and elevated inflammatory mediators such as interleukin-6 and tumour necrosis factor-alpha. Together, these pathways may support immune suppression, tumour growth, angiogenesis, metastatic potential, treatment resistance, and recurrence. The manuscript also highlights the possible relevance of stress management, nutritional support, and weight control as supportive strategies in cancer care. However, much of the available evidence is derived from preclinical, mechanistic, and observational studies, limiting causal interpretation and direct clinical translation. Integrated approaches that include stress reduction and obesity management may be useful adjuncts in oncology care, but their effects on cancer-related biomarkers and clinical outcomes require further investigation through well-designed prospective and interventional studies.