Physical Activity and Nutrition in Primary and Tertiary Prevention of Colorectal Cancer.

BACKGROUND: Lifestyle factors play a pivotal role in the primary and tertiary prevention of colorectal cancer. The purpose of this review article is to summarize data concerning the effect of the lifestyle factors physical activity (PA) and nutrition in primary and, more importantly, tertiary prevention of colorectal cancer (CRC). METHODS: Focusing on the influence of lifestyle factors on prognosis und quality of life (QOL), a comprehensive literature search of clinical studies published mainly in the years 2000 until 2015 was performed and the current knowledge based on these clinical studies reviewed. RESULTS: Besides avoiding risk factors (such as smoking and overindulgence in alcohol), healthy weight, regular and moderate PA as well as a diet which contains fruit, vegetables, poultry, and fish (so-called 'Mediterranean' diet) may reduce the risk of the disease significantly. Patients already diagnosed with CRC can also actively improve the prognosis of CRC and QOL by changing their lifestyle. Patients commencing moderate exercise and modifying their eating habits in terms of a 'Mediterranean' diet can reduce cancer-specific and overall mortality by up to 40% and significantly increase their quality of life already during chemotherapy. Therefore, moderate physical exercise, calorie restriction, and a Mediterranean dietary pattern for patients with CRC should be recommended by physicians treating these patients. In fact, the World Cancer Research Fund/American Institute for Cancer Research (AICR/WCRF) systematic literature review from 2007 shows that the lifestyle changes recommended after diagnosis are the same for primary prevention of this disease. CONCLUSION: Lifestyle changes such as moderate PA and a Mediterranean diet significantly improve the QOL as well as the prognosis of patients suffering from colorectal disease. However, the effect of lifestyle changes is mostly based on observational studies, while only few studies are prospective and none are randomized. Therefore, these observational studies warrant controlled randomized trials to prove the effectiveness of lifestyle interventions on QOL and cancer recurrence.