DIET, LIFESTYLE, AND CANCER: FROM PREVENTION TO SURVIVAL

Abstract

According to the American Cancer Society, at least 42% of newly diagnosed cancers in the US in 2022 could potentially be prevented, including the 18% of all cancers caused by obesity, alcohol intake, poor nutrition, and physical inactivity. Based on the comprehensive evaluation of current evidence, the World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR) issued in 2018 seven recommendations on diet, physical activity, and weight management for cancer prevention. For Chapter 1 and 2, we focused on how to better evaluate the adherence to the 2018 WCRF/AICR cancer prevention recommendations and the synergistic effect of adhering to the recommendations. For Chapter 3, the focus was on alcohol intake, one of the major diet factors in the 2018 WCRF/AICR recommendations. Chapter 1 investigated different scoring systems to evaluate adherence to the 2018 WCRF/AICR cancer prevention recommendations and the associations with risk of cancer. We found that greater adherence to the 2018 WCRF/AICR cancer prevention recommendations was associated with lower risk of total cancer, obesity-related cancer, alcohol-related cancer, smoking-related cancer, digestive system cancer, and major individual cancer sites in two prospective cohorts in the US. A score that upweighted the adiposity, physical activity, and alcohol recommendations yielded stronger associations. In Chapter 2, we found that better adherence to the 2018 WCRF/AICR cancer prevention recommendations after colorectal cancer diagnosis was associated with better survival among colorectal cancer patients. We only found weak, nonsignificant associations for the diet score, suggesting that dietary recommendations formulated for cancer prevention may not optimally reflect dietary factors for improving colorectal cancer survivorship. In Chapter 3, in a large international consortium with 19 cohorts, we found that total alcohol intake was positively associated with risk of all advanced forms of prostate cancer. The magnitude of the associations for moderate alcohol consumption was similar and modest across outcomes, indicating minimal clinical importance for prostate cancer prevention. Findings were generally similar across alcohol intake from beer, liquor, and wine for aggressive and high-grade prostate cancer, whereas stronger associations were shown between heavy beer/liquor drinkers with the risk of fatal/advanced, fatal, and advanced prostate cancer. In conclusion, better adherence to the 2018 WCRF/AICR cancer prevention recommendations was associated with decreased risk of cancer and better survival among CRC patients. However, alcohol, an important risk factor in the recommendations, may not be a clinically important factor for prostate cancer prevention.