Sugar-rich foods and colorectal cancer recurrence

This study investigated whether diets rich in carbohydrates influence recurrence rates in patients treated for colorectal cancer. The main finding was that a higher glycemic (sugar) load and carbohydrate intake were associated with a greater risk of cancer recurrence.  

Dietary factors, as well as body weight and physical activity, play an important role in the development of colorectal cancer. It is hypothesized that eating foods rich in carbohydrates (or sugars) contributes to worse treatment outcomes. The glycemic load is an objective measurement of sugar intake. It is calculated by taking into account the amount of carbohydrates in each food, how fast they elevate blood sugar levels (the glycemic index) and the frequency of consumption. A high glycemic load increases total insulin production in order to process the excess sugar. High levels of insulin have been previously linked to colorectal cancer development.  

The present study enrolled 1011 patients with stage III colorectal cancer. They were selected from another trial which compared two post-surgical chemotherapy regimens. Participants were given two questionnaires about eating habits, one midway through chemotherapy and another one 6 months after completing their treatment. The glycemic load was calculated based on the answers. Total follow-up was approximately 7.3 years. The disease-free survival (time before cancer recurrence) was almost 2 times (1.79) shorter in patients with the highest glycemic load compared to those with the lowest glycemic load. This was significant only in overweight patients. An increased total carbohydrate intake was also associated with reduced disease-free survival.  

The authors concluded that a higher glycemic load lowers disease-free survival in overweight patients with colorectal cancer.

These results were however obtained based on information collected using questionnaires. Since patients were part of another clinical trial, their sugar intake may also not reflect trends found in the general population.