This chapter outlines cancer prevention as the most effective strategy to reduce global cancer incidence and mortality. Primary prevention targets the earliest stages of tumorigenesis by minimizing modifiable risk factors such as smoking, infections, obesity, UV exposure, and chronic inflammation. Vaccination, lifestyle optimization, and avoidance of carcinogens can prevent a substantial proportion of cancers. Physical activity exerts broad anticancer effects by enhancing immune surveillance, improving metabolic health, modulating hormones, and reducing inflammation. Diet and the gut microbiome further influence cancer risk, with disparities emerging through environmental and socioeconomic factors. Secondary prevention focuses on detecting premalignant or early-stage tumors through validated screening programs including mammography, Pap/HPV testing, colonoscopy, and low-dose CT. Challenges include overdiagnosis, false results, and lead-time bias. Advances in biomarkers, multicancer early detection tests, liquid biopsies, and artificial intelligence (AI) promise more precise, risk-adapted screening. Survivorship care addresses long-term toxicities from therapy, cardiovascular, endocrine, neurocognitive, pulmonary, reproductive, and psychological, particularly relevant in childhood cancer survivors. Chronic comorbidities and stress significantly influence outcomes, while early palliative care improves quality of life and survival. Multidisciplinary survivorship programs provide structured follow-up, late-effect monitoring, and lifestyle guidance, aiming to optimize long-term health and functionality.