The Inflammatory Footprint of Anti-Breast Cancer Treatments and Psychosocial Factors in Women Undergoing Chemotherapy

<b>Background/Objectives</b>: Despite the well-recognized role of inflammation in breast cancer course, the biological mechanisms involved in its pathophysiology are complex, heterogeneous, and still unclear. However, evidence shows that cancer treatments and stress system responses impact the patient's inflammatory status. We aim to analyze the inflammatory footprint of anti-breast cancer treatments and psychosocial factors by observing the evolution of inflammatory and psychosocial markers pre- and post-chemotherapy; to examine the associations between pro- and anti-inflammatory cytokines with psychosocial factors after chemotherapy; and to identify vulnerability/resilience variables that may improve patients' referral for psycho-oncological interventions before/after chemotherapy. <b>Methods</b>: We performed a well-controlled cohort study of premenopausal women diagnosed with stage I to III breast cancer undergoing chemotherapy. Patients were longitudinally evaluated at pre-chemotherapy (post-surgery in the adjuvant cohort) and post-chemotherapy. Both evaluations included clinical, immunological, and psychosocial data. <b>Results</b>: A significant decrease in TNF-α (<i>p</i> = 0.001) was observed in the adjuvant cohort compared to the neoadjuvant cohort. After chemotherapy, we found a significant decline in IL-17a, TNF-α, and IL-10 (<i>p</i> = 0.000, 0.000, 0.020), reinforcing the influence of chemotherapy on immunocompetence. Significant relations (<i>p</i> < 0.01) were found between the inflammatory biomarkers that decreased post-chemotherapy and psychosocial factors. Venting and instrumental/emotional support coping played the greatest role in immunological-psychological interactions. <b>Conclusions</b>: The findings confirm an inflammatory footprint, linking the complex interplay between breast tumors, anti-breast cancer treatments, and psychosocial factors. By supporting the immunoregulatory role of biological and psychosocial factors in immunocompetence, our findings bring potential insights into a biopsychosocial approach that targets both survival and psychological adjustment outcomes.