Physical activity in the prevention and treatment of colorectal carcinoma

Abstract

Background: Colorectal carcinoma is the most common type of tumor in Western countries. The risk of developing colorectal carcinoma depends both on genetic factors (familial predisposition) and on lifestyle-related factors such as body-mass index, level of physical activity, and nutritional behavior. Regular physical activity is important in primary prevention, and there is also evidence that the prognosis after treatment of a colorectal carcinoma can be improved by exercise.

Methods: The PubMed database was searched for relevant articles that appeared in the last 10 years, and selected articles were evaluated.

Results: Cross-sectional studies have shown that regular physical activity (ca. 7 hours of brisk walking per week) lowers the risk of colon carcinoma by 40%. Physical activity also improves the outcome of patients already diagnosed with colorectal carcinoma: for example, patients with advanced disease (UICC stage II or III) have been found to survive significantly longer if they perform 4 hours of brisk walking per week, or the equivalent degree of physical exercise.

Conclusions: Cross-sectional studies show that physically active persons are less likely to develop colorectal carcinoma than physically inactive persons, and that they have better outcomes in the event that they do develop the disease. The positive findings with respect to secondary prevention still need to be confirmed in interventional trials, but in primary prevention, at least, physical activity should be actively promoted, along with other beneficial lifestyle habits and screening measures.

Keywords: cancer prophylaxis; cancer therapy; colorectal carcinoma; physical activity; prevention.

Figure 1

Possible relationships between overweight, inactivity, insulin resistance, and tumorigenesis

Figure 2

Influence of physical activity in MET × hours/week on disease-specific mortality in patients with colorectal carcinoma (MET, metabolic equivalent task). From (18): Meyerhardt JA, et al.: Physical activity and survival after colorectal cancer diagnosis. J Clin Oncol 2006; 24: 3527–34; reproduced by kind permission of the American Society of Clinical Oncology

Figure 3

Hazard ratio of increased physical activity by sex, body-mass index (BMI), lymph node involvement (LN), type of chemotherapy, age, and disease severity. From (21): Meyerhardt JA, Heseltine D, Niedzwiecki D, et al.: Impact of physical activity on cancer recurrence and survival in patients with stage III colon cancer: findings from CALGB 89803. J Clin Oncol 2006; 24: 3535–41; reproduced by kind permission of the American Society of Clinical Oncology

Figure 4

Association of change in physical activity (increase, no change, decrease) before and after diagnosis of colon carcinoma with disease-specific mortality and overall mortality. In comparison with women who did not change their exercise behavior (n = 203), patients who increased their sporting activity (n = 144) had an adjusted hazard ratio (HR) of 0.48 (95% confidence interval [95% CI] 0.24 to 0.97) for colorectal carcinoma-specific mortality and an adjusted HR of 0.51 (95% CI 0.30 to 0.85) for overall mortality. In contrast, women whose sporting activity decreased (n = 176) showed a moderate, albeit non-significant, increase in tumor-specific mortality (HR 1.32, 95% CI 0.74 to 2.34) and overall mortality (HR 1.23, 95% CI 0.79 to 1.91). From (18): Meyerhardt JA, et al.: Physical activity and survival after colorectal cancer diagnosis. J Clin Oncol 2006; 24: 3527–34; reproduced by kind permission of the American Society of Clinical Oncology