Bidirectional Relations Between Anxiety, Depression, and Cancer: A Review

Epidemiological evidence continues to accumulate on the effect of stress and depression on cancer initiation and progression. Depression has been introduced as an independent predictor of increased cancer mortality. At the same time, early intervention for depression increases the survival rate. Even some evidence has given prognostic value for depression to predict cancer recurrence and mortality. This article presents current evidence on the correlations of molecular mechanisms of cancer and depression through; I. The evidence shows the role of pre-existing depression and anxiety in the development and progression of cancer. II. The Immune system performs a crucial role in stress, depression, and cancer. III. The role of stress and depression-induced inflammation. IV. The evidence has proposed that cancer may result in depression and the effect of depression on cancer outcomes. In conclusion, the importance of preventive interventions to monitor patients' mental health during cancer treatment is very significant and should not be underestimated. In other words, the initial interventions can improve depressive symptoms and increase cancer survival. On the other hand, by identifying key biomarkers of depression, physicians can identify cancer patients at risk for depression or those who may not respond to routine treatments. Revealing the molecular mechanism of the cancer microenvironment in the development of comorbidities promises innovative therapeutic options for cancer. Identifying these mechanisms opens a new avenue in identifying cancer patients at risk for depression and can also provide considerable potential in identifying depressive patients prone to cancer.