Bowel cancer is one of the most common cancers in the West, and is strongly linked to dietary factors, especially high intakes of red meat, fat, and refined sugars. Survival rates are generally poor, with less than half of those affected still alive five years after diagnosis.
The researchers studied the energy intakes before diagnosis of 148 patients (97 men and 51 women) who had undergone successful surgery to remove cancerous growths from their bowel. The patients were monitored for up to 10 years.
Forty six patients died within five years, the strongest predictor of death being how advanced the tumour was when first diagnosed. Factors increasing the length of survival were female sex, being under 65, and location of the tumour. Exercise, alcohol consumption, and smoking before diagnosis made little difference to survival rates.
But energy intake also affected survival rates, with patients on low and moderate energy intakes before diagnosis around three times as likely to die within five years as those on a high intake.
Altogether, six out of 50 patients (12%) on a calorie laden diet died within five years, compared with 22 of 48 on a moderately high calorific intake (46%), and 18 of 50 (36%) on a low calorie diet. The research was unable to identify a specific food or nutrient that increased survival.
The finding is nevertheless a little surprising, given that a calorie laden diet seems to increase the risk of developing bowel cancer in the first place, and calorie restriction is known to increase immune cell activity, say the authors. But they speculate that a high energy diet may select for specific forms of bowel cancer that carry a better chance of survival.
Gut 2003; 52: 868-73
Journal
Gut