Diet and Lifestyle in Survivors of Colorectal Cancer
Junga Lee, PhDa, Justin Y. Jeon, PhDa and Jeffrey A. Meyerhardt, MD, MPHb∗jmeyerhardt@partners.org, aExercise Medicine Center for Cancer and Diabetes Patients, Department of Sport and Leisure Studies, 50 Yonsei-ro, Yonsei University, Seoul 120-749, Korea; bDepartment of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
∗Corresponding author.
Much research supports the association between diet and lifestyle in the development of colorectal cancer. Recent studies have demonstrated an association between various energy balance host factors (obesity, physical inactivity, and certain dietary factors) and outcomes. This review summarizes the impact of modifiable lifestyle factors, including prediagnosis and postdiagnosis adiposity, physical activity, and diet, on the prognosis of patients with colorectal cancer. The article focuses on associations of these factors in survivors of stage I to III colorectal cancer, and summarizes the possible mechanisms for the association between modifiable lifestyle factors and the prognosis of patients with colorectal cancer.
Keywords
Colorectal cancer
Cancer survival
Lifestyle factors
Epigenetics
Key points
• Lifestyle factors that include obesity, physical activity, and diet are emerging as potential critical elements in improving survival outcomes for colorectal cancer.
• Changes in individual health behaviors both before and after a diagnosis of colorectal cancer may improve outcomes of survivors.
• Studies have indicated that maintaining a normal weight, participating in regular physical activity, and eating a healthy diet may be important preventive steps leading to improved survival outcomes.
• Epigenetic studies have demonstrated, at the cellular level, the possible mechanisms of colorectal cancer that can be positively influenced by changing lifestyle.
Introduction
The American Cancer Society estimates that there are more than 1.1 million survivors of colorectal cancer in the United States.1 Survivors of colorectal cancer constitute 10% of the total number of cancer survivors, and the number is increasing.2 Both genetic and lifestyle factors contribute to cancer development and the prognosis of colorectal cancer. Because lifestyle factors such as obesity, physical inactivity, diet, smoking, and alcohol consumption are potentially modifiable3,4 while genetic factors are not, much attention has been paid to the impact of lifestyle factors on the incidence and prognosis of colorectal cancer.
Changing these modifiable factors toward practice of a healthy lifestyle may be crucial components of cancer treatment in addition to standard treatments in preventing recurrence and improving survival of patients with colorectal cancer. Although an increasing number of studies have examined the association of diet and lifestyle factors with cancer recurrence and survival outcome in patients with locally advanced colorectal cancer,5–9 it is important to distinguish whether these exposures were measured before or after cancer diagnosis. For example, adiposity before diagnosis and after diagnosis may have a different impact on survival outcomes of patients with colorectal cancer. Exposures after diagnosis associated with prognosis of cancer may provide important implications on directing recommendations to cancer survivors. However, if an association exists only between prediagnosis adiposity and prognosis of colorectal cancer, it is less certain how to guide a patient, although such data may be important in understanding the biology of colorectal cancer.
This review summarizes the associations of modifiable lifestyle factors, including prediagnosis and postdiagnosis adiposity, physical activity, and diet, on the prognosis of patients with colorectal cancer. Given that most published data to date are from patients without metastatic disease, the focus here is on associations of these factors in survivors of stage I to III colorectal cancer. This article also summarizes the possible mechanisms for the association between modifiable lifestyle factors and the prognosis of patients with colorectal cancer.
Association between the prediagnosis lifestyle factors and risk of mortality in survivors of colorectal cancer
Adiposity
Several studies have examined the association between prediagnosis adiposity and the prognosis of colorectal cancer (Table 1).6,10–13 These studies used a variety of metrics for adiposity, including body mass index (BMI; calculated as weight in kilograms divided by height in meters squared, ie, kg/m2), waist-hip ratio (WHR), and waist circumference (WC). Campbell and colleagues6 examined 2303 men and women with stage I to III colorectal cancer and reported that those with BMI higher than 25 had worse colorectal cancer–specific mortality and all-cause mortality. Similarly, Doria-Rose and colleagues10 studied 633 postmenopausal women with colorectal cancer and reported that obese patients (BMI ≥30) had a 2.1-fold higher risk of colorectal cancer–specific mortality and all-cause mortality compared with patients of normal weight.
Table 1
Prospective cohort studies of prediagnosis body mass index (BMI, kg/m2) and survival outcomes in patients with colorectal cancer
| Doria-Rose, et al,10 2006, Wisconsin Cancer Reporting System, USA | 633 female
Colon and rectal | 9.4 | CRC-specific mortality | Age, stage, postmenopausal hormone use, and smoking |
| Prizment et al,11 2010, Iowa Women’s Health Study, USA | 1096 female
Colon | 20 | CRC-specific mortality | Stage, age, education, and smoking |
| 25.0–29.9 | 1.18 (0.87–1.52) |
| 25.0–29.9 | 1.12 (0.89–1.41) |
| Kuiper et al,12 2012, Women’s Health Initiative, USA | 1339 female
Colon and rectal | 11.9 | CRC-specific mortality | Age, study arm, BMI, tumor stage, ethnicity, education, alcohol, smoking, hormone therapy use |
| 25.0–29.9 | 0.77 (0.52–1.13) |
| 25.0–29.9 | 0.90 (0.66–1.23) |
| Campbell et al,6 2012, Cancer Prevention Study-II Nutrition Cohort, USA | 2303 both genders
Colon and rectal | 16 | CRC-specific mortality | Age, sex, smoking status, BMI, red meat intake, tumor stage, leisure time spent sitting, education |
| 25.0–29.9 | 1.19 (0.80–1.78) |
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