Obesity and overweight in the modern world have reached the scale of a pandemic. Therefore, already by 2016, 39% of adults over 18 years old had excessive body weight, 13% were obese. Over the past 40 years, the number of people suffering from obesity and overweight has almost tripled, and the number of children with overweight has more than quadrupled. In parallel, the number of cases of cancer associated with obesity has increased significantly. The review presents an assessment of the current epidemiological aspects of oncology in persons with overweight and obesity highlighting the main etiology and pathogenesis factors of cancer development in comorbid pathology taking into account age and gender characteristics, and an analysis of the most optimal ways of cancer prevention in persons with obesity and overweight. It was shown that 13 types of oncopathology are associated with overweight and obesity. The epidemiology of oncopathology associated with obesity and overweight differs depending on gender, age, and form of obesity, bad habits, degree of obesity, and other factors. It is emphasized that the burden of malignant neoplasms associated with obesity is extremely high and ranks second after smoking. The pathways for cancer prevention in obese patients are to achieve normal body mass through adequate exercise and diet. It is shown that with overweight and obesity, a decrease in the risk of morbidity with certain types of cancer can be achieved by taking metformin, melatonin preparations, antioxidants, antiandrogens and antiestrogens. A long-term perspective for the development of cancer prevention is presented in the light of the prevention of obesity and overweight maintaining a healthy lifestyle and the introduction of pharmaceutical cancer prevention programs.