Diabetes mellitus (DM) has been increasingly recognized for its association with cancer risk and outcomes. Individuals with diabetes are at a higher risk of developing certain types of cancer compared to the general population. The relationship between DM and cancer is multifactorial, involving shared risk factors such as obesity, sedentary lifestyle, and dietary habits. Mechanisms underlying this association include hyperinsulinemia, insulin resistance, chronic inflammation, and alterations in growth factors like insulin-like growth factor (IGF) and adipokines. These metabolic disturbances can promote carcinogenesis by facilitating cell proliferation, inhibiting apoptosis, and enhancing angiogenesis. Moreover, diabetes management, including medications like metformin, has been studied for its potential protective effects against certain cancers. However, the impact of diabetes on cancer outcomes remains complex, influencing prognosis and treatment responses. Integrated approaches addressing both diabetes control and cancer screening are crucial in clinical practice to mitigate the dual burden of these chronic conditions and improve overall patient outcomes.