A person’s diet—particularly carbohydrates and sugar—could lead to certain neck or head cancers coming back.

Researchers from the University of Illinois at Urbana-Champaign have found that consuming higher amounts of carbohydrates and various forms of sugar a year prior to treatment for head or neck cancer could increase risk of cancer recurrence and mortality. However, more data is needed.

“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,” lead author Anna Arthur, a professor of food science and human nutrition at the University of Illinois, said in a statement. “The next step would be to conduct a randomized clinical trial to test whether carbohydrate restriction has a protective effect on survival rates.”  

During the study, the researchers tracked the pre-and-post treatment diets and ultimate health outcomes of more than 400 cancer patients for an average of 26 months after they were first diagnosed and treated for squamous-cell carcinoma of the head or neck.

All of the participants, which were patients of the University of Michigan Head and Neck Specialized Program of Research Excellence, were asked to track their intake of food, beverages and supplements for a year prior to diagnosis and a year following treatment using the Harvard Food Frequency Questionnaire.

The researchers found that patients who consumed more total carbohydrates and sugars in the year preceding cancer treatment had an increased risk of mortality from any cause during the follow-up period.

More than 17 percent of the patients saw a reoccurrence of cancer, while 42 percent of the patients died from it. Another 70 participants in the study died from other causes.

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 percent of participants were diagnosed when the disease was at stage 3 or stage 4. Average age at diagnosis was about 61.

Those who had oral cavity cancer and consumed greater amounts of total carbohydrates, total sugars and simple carbohydrates had higher mortality rates. However, the researchers did not find a similar connection with 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.

On the other side, the researchers found that consuming about 67 grams of moderate fats and starchy foods daily after cancer treatment lowered the risks.

“Our results, along with the findings of other studies, suggest that diet composition can affect cancer outcomes,” co-author Amy M. Goss, a professor of nutrition sciences at the University of Alabama, Birmingham, said in a statement. “We'd like to determine if this is true using a prospective, intervention study design and identify the underlying mechanisms. For example, how does cutting back on sugar and other dietary sources of glucose affect cancer growth?”

The study was published in the International Journal of Cancer