Beyond Standard Adjuvant Therapy for Colon Cancer: Role of Nonstandard Interventions

Epidemiologic and scientific research indicates that diet and other lifestyle factors have a significant influence on the risk of developing colorectal cancer. Obesity, consumption of red meat, a Western pattern diet, alcohol, and smoking influence one's risk of developing colorectal cancer while physical activity, vitamin D, postmenopausal estrogen use, aspirin, and nonsteroidal anti-inflammatory drugs (NSAIDs) decrease one's risk. Until recently, it was largely unknown if any of these modifiable factors influence the outcomes of patients already diagnosed with colorectal cancer. However, data are emerging of factors that may influence disease recurrences and mortality for colorectal cancer survivors. Prospective observational studies have shown that increased exercise after diagnosis and avoidance of a Western pattern diet are associated with reduced risk of cancer recurrence and improved overall survival in early-stage colorectal cancer after standard therapy. Patients with class II and III obesity (body mass index [BMI] ≥35 kg/m2) have a modestly increased risk of recurrence. Regular use of aspirin or cyclooxygenase (COX)-2 inhibitors decrease recurrence rates and increase serum vitamin D levels. In contrast, change of weight after diagnosis or smoking status (never, past, or current) are not associated with outcomes after diagnosis. The data supporting these observations will be reviewed, potential mechanisms of actions will be discussed, and the next steps forward will be proposed.