The role of body mass index, physical activity, and diet in colorectal cancer recurrence and survival: a review of the literature.

The role of dietary and other lifestyle factors in colorectal cancer recurrence and survival is largely unknown. We conducted a review to summarize the evidence from epidemiologic studies that examined the association of body mass index (BMI), physical activity, and nutrition with colorectal cancer recurrence and survival. We searched MEDLINE and EMBASE for relevant epidemiologic studies published up to March 2010 by using MeSH terms and related key words. We identified 36 articles that were based on 31 independent studies on BMI (n = 21), physical activity (n = 6), or nutrition (n = 12) in relation to colorectal cancer recurrence and survival. Studies were generally based on follow-up of cases in existing patient series, case-control or cohort studies, or chemotherapy trials. BMI, physical activity, and nutrition mostly referred to the time at or before diagnosis. Only 10 studies assessed BMI (n = 1), physical activity (n = 4), or nutrition (n = 5) after diagnosis. There may be an association between higher BMI and body fatness before or at the time of diagnosis and a higher all-cause mortality or colorectal cancer-specific mortality or recurrence, although results may differ by sex, tumor location, and molecular subtype. There may be a relation between higher leisure-time physical activity after diagnosis and a lower all-cause or colorectal cancer-specific mortality. For dietary factors, statistically significant associations were only shown for single foods, nutrients, and dietary patterns in single studies. In conclusion, only a paucity of data is available on the effect of dietary and other lifestyle factors on colorectal cancer recurrence and survival. Thus far, no clear conclusions can be drawn. Future studies are warranted, particularly on postdiagnosis BMI and diet.