Lifestyle Factors and Cancer: A Narrative Review.

Lifestyle factors and their impact on cancer prevention, prognosis, and survivorship are increasingly recognized in the medical literature. Lifestyle factors are primarily defined here as diet and physical activity. We conducted a narrative review of the primary published data, including randomized controlled trials and prospective studies, on the impact of primary lifestyle factors on oncogenesis and clinical outcomes in the preventative and survivorship setting. First, we discuss the oncogenic mechanisms behind primary lifestyle factors (diet, physical activity and, within these 2, obesity). Then, we discuss the impact of adherence to lifestyle guidelines and dietary patterns on cancer incidence based on primary data. Owing to the plethora of published literature, to summarize the data in a more efficient manner, we describe the role of physical activity on cancer incidence using summative systematic reviews. We end by synthesizing the primary data on lifestyle factors in the survivorship setting and conclude with potential future directions. In brief, the various large-scale studies investigating the role diet and physical activity have reported a beneficial effect on cancer prevention and survivorship. Although the impact of single lifestyle factors on cancer incidence risk reduction is generally supported, holistic approaches to address the potential synergistic impact of multiple lifestyle factors together in concert is limited. Future research to identify the potentially synergistic effects of lifestyle modifications on oncogenesis and clinical outcomes is needed, particularly in cancer subtypes beyond colorectal and breast cancers.