Artificial light at night (ALAN) has become an inescapable component of modern life, shaping environments in homes, workplaces, and urban spaces. While technological advances in lighting have improved visibility and safety, growing epidemiological evidence links chronic exposure to ALAN with increased cancer risk, particularly hormone-sensitive cancers such as breast and prostate cancer. This review explores the biological mechanisms underlying this association, focusing on circadian rhythm disruption, melatonin suppression, and light-induced oxidative stress and DNA damage. We critically examine epidemiological studies that reinforce these mechanisms and highlight the role of smart lighting technologies in mitigating these risks. Smart lighting systems—featuring tunable LEDs, sensors, and adaptive control—offer a promising solution by aligning artificial lighting with natural circadian patterns. This review evaluates how circadian-optimized lighting designs can preserve melatonin levels, reduce biological stressors, and potentially serve as a non-invasive cancer prevention strategy. Additionally, we address the challenges of implementation, the limitations of current research, and the need for interdisciplinary studies to validate long-term health outcomes. Ultimately, this review emphasizes the importance of leveraging smart lighting innovation not only for energy efficiency and comfort but also as a proactive tool in public health strategies against cancer.