Cancer risk due to lifestyle and environmental factors can be prevented

Almost four in every 10 new cases of cancer in Germany are attributable to lifestyle and environmental factors. These include primarily smoking, low physical activity, overweight, and infections. Hermann Brenner and his group of authors from the German Cancer Research Center (DKFZ) report on how these risk factors affect the number of cancer cases in Germany in concrete terms, in this themed issue of Deutsches Ärzteblatt International (Dtsch Arztebl Int; 115: 571-593).

In their series of articles, the Heidelberg-based authors determined the proportion of new cancer cases in a particular segment of the population among all new cancers expected for 2018. The calculation is based on population projections, published relative risks, and cancer incidence and exposure data for 35-84 year olds in Germany.

In the current year, an estimated 85 072 cases of cancer will have been caused by smoking. This corresponds to 19% of all new cases. In men, the proportion of lung cancers due to tobacco consumption is 89% and in women, 83%. Overweight and a lack of physical activity/exercise account for 7% and 6% of the expected cancer burden, respectively, and constitute the main risk for uterine and renal cancers. In overweight persons, the risk of liver cancer is also raised, while a lack of physical exercise also contributes to lung cancer. Bacterial or viral infections cause 17 600 incident cases, which is 4% of expected new cancer cases. Infection with Helicobacter pylori and human papillomaviruses have a major role in this setting. A lower but still important proportion of new malignancies is due to high alcohol consumption, high intake of processed meat, or low intakes of dietary fiber, fruits, and vegetables. Additional risk factors include indoor radon, particulate matter, or sunbed use.

The authors make a plea for more stringent prevention measures in terms of tobacco and alcohol consumption, overweight, unhealthy diet, and lacking physical exercise. They also call for targeted preventive measures regarding infections and environmental factors. But they highlight that further research is needed in order to identify and quantify environmental risks more comprehensively.