High carbohydrate intake may up cancer recurrence risk

Eating high amounts of carbohydrates and sugar during the year prior to treatment can increase the risks of head and neck cancer recurrence and mortality, a study has found.

However, eating moderate amounts of fats and starchy foods such as whole grains, potatoes and legumes after treatment could have protective benefits, reducing patients' risks of disease recurrence and death, said Anna E Arthur, a professor at the University of Illinois in the US.

Researchers tracked the pre- and post-treatment diets and health outcomes of more than 400 cancer patients.

Participants were followed for an average of 26 months after they were first diagnosed and treated for squamous-cell carcinoma of the head or neck.

Participants' typical intake of food, beverages and supplements was assessed for the year prior to diagnosis and for one year post-treatment.

Patients who consumed the lowest amounts of simple carbohydrates - which included refined grains, desserts and sugar-sweetened beverages - consumed about 1.3 servings daily, compared with about 4.4 servings by patients who were considered high intake.

Patients who consumed the most total carbohydrates and sugars - in the forms of sucrose, fructose, lactose and maltose - in the year preceding cancer treatment were at greater risk of mortality from any cause during the follow-up period, Arthur said.

Among the study population, the most commonly diagnosed cancers were in the oral cavity and the oropharynx, which includes the tonsils, the base of the tongue and surrounding tissues.

More than 69 per cent of participants were diagnosed when the disease was at stage 3 or stage 4. Patients' average age at diagnosis was about 61.

During the follow-up period, more than 17 per cent of patients experienced recurrence of their cancer, and 42 patients died from it. Another 70 participants died from other causes, according to the study published in the International Journal of Cancer.

Associations among carbohydrate intake and patient outcomes differed by cancer type and stage, Arthur said.

Higher mortality rates were found among people with oral cavity cancer who consumed the greatest amounts of total carbohydrates, total sugars and simple carbohydrates, but the researchers found no such associations among people who had oropharyngeal cancers.

Likewise, high carbohydrate consumption and glycemic load were significantly associated with increased risk of mortality from any cause among people with cancers in stages 1 to 3, but not in patients with stage 4 cancers.

"Although in this study we found that higher total carbohydrate and total sugar were associated with higher mortality in head and neck cancer patients, because of the study design we can't say that there's a definitive cause-effect relationship," said Arthur.

"The next step would be to conduct a randomized clinical trial to test whether carbohydrate restriction has a protective effect on survival rates," she said.

Consuming a moderate amount - about 67 grams - of various forms of fat and starchy foods daily after cancer treatment appeared to provide some beneficial effects, lowering participants' risks of mortality and cancer recurrence.

"Our results, along with the findings of other studies, suggest that diet composition can affect cancer outcomes," said Amy M Goss, a professor at the University of Alabama, Birmingham.