The link between lifestyle and colorectal cancer has been increasingly studied, highlighting the potential impact of the standard American diet and inactivity on colorectal cancer development and outcomes.
According to the Centers for Disease Control and Prevention (CDC), colorectal cancer is the third most common cancer and the second most common source of cancer death in American men and women.
The most commonly cited risks for development of colorectal cancer (CRC) include age, family history, inflammatory bowel disease, and genetic syndromes. However, research has also linked colon cancer risk to several lifestyle factors including diets low in fiber, vegetables, and fruit and high in fat, lower physical activity, and obesity. Likewise, CRC has been linked to tobacco and alcohol use.1,2
The question remains, however, how should providers counsel patients on lifestyle factors and nutrition with respect to colorectal cancer?
Jeffrey Meyerhardt, MD, MPH, associate professor of medicine at Harvard Medical School and medical oncologist at Dana-Farber Cancer Institute in Boston, MA, noted in an email to Cancer Therapy Advisor, “For patients already diagnosed with colon cancer, the data are just emerging in the past 10 years regarding diet and lifestyle exposures. There are multiple studies now associating physical activity with outcomes in colon cancer survivors, and there are ongoing clinical trials to better study this. Several dietary exposures have been associated with increased risk of recurrence in non-metastatic colon cancer survivors, including high glycemic load, Western pattern diet and high carbohydrate intake. There are also observational studies suggesting aspirin and COX-2 inhibitors lower risk of recurrence, and there are ongoing randomized clinical trials to test this question.”
Lifestyle factors seem to play a role in CRC outcomes. For instance, a baseline BMI of greater than 35 kg/m2 was tied to a higher risk of recurrence or other primary cancers in a cohort of patients with colon cancer.
Likewise, a higher risk of recurrence and mortality was associated with a greater consumption of the Western diet which is high in processed foods, fat, and red meat in dietary analysis of participants in the CALGB 89803 study.
Further analysis of the participants in the CALGB 89803 study for stage III colon cancer survivors, tied a self-report of 6 or more hours of physical activity weekly to reduction in recurrence and improved survival.3
“The most important thing is to bring up the topic and discussion with patients; realizing behavior changes can be hard,” Dr Meyerhardt continued. “Working with and involvement of nutritionists, physical therapists, exercise consultants, and trainers can be very helpful to guide patients. An important consideration is that diet and lifestyle may help risk of other health problem down the line for the colon cancer survivors.”
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High fiber consumption in the form of grains, fruit, and vegetables is associated with a shorter intestinal transit time and higher production of short-chain fatty acids related to augmentation of bacterial fermentation. Other factors that possibly link fiber consumption and CRC risk include anticancer phytochemicals found in green leafy and cruciferous vegetables, anti-inflammatory functions, and cell cycle regulatory interference by short-chain fatty acids.4
For instance, the observational European Prospective Investigation into Cancer and Nutrition (EPIC) study of more than 500 000 participants concluded that doubling the intake of dietary fiber by populations with a low intake could reduce CRC risk by 40%.5