The study – published in the Journal of the National Cancer Institute – reveals data to suggest that people who survive colon cancer, but whose diet is heavy in complex sugars and carbohydrate-rich foods are up to 80% more likely to have a recurrence of the disease than people who eat a better balance of foods. Indeed the research team show that the risk is even higher in people who are overweight or obese.
Led by Dr Jeffrey Meyerhardt from the Dana-Farber Cancer Institute in Boston, USA, the authors noted their finding suggests that diet and lifestyle modification can have a role in improving cancer survival and the risk of recurrence.
"Our study certainly supports the idea that diet can impact the progression of colon cancer, and that patients and their doctors should consider this when making post-treatment plans,” said Meyerhardt.
However, the team added that because people who consumed a high glycaemic load or more carbohydrates after cancer diagnosis may have consumed a similar diet before diagnosis, “we cannot exclude the possibility that individuals with these dietary exposures acquire tumours that are biologically more aggressive."
“Further research is needed to confirm our findings,” said the lead researchers.
The new research involved data from 1,011 stage three colon cancer patients who had undergone surgery and participated in a National Cancer Institute-sponsored Cancer and Leukemia Group B clinical trial of follow-up chemotherapy for their disease.
In the trial, participants reported their dietary intake during and six months after the trial. The researchers then tracked patients' total carbohydrates, in addition to glycaemic index and glycaemic load, and looked for a statistical connection between these measures and the recurrence of colon cancer.
The analysis revealed that participants with the highest dietary levels of glycaemic load and carbohydrate intake had an 80% increased risk of colon cancer recurrence or death compared with those who had the lowest levels.
Meyerhardt and his team noted that among patients who were overweight or obese, this increase was even greater.
Avid sugar consumers
In an accompanying editorial, Dr Neal Meropol and Dr Nathan Berger, of Case Western Reserve University School of Medicine, USA, add context by explaining that the new data is consistent with an observation more than 50 years ago that cancer cells are "avid sugar consumers."
"Although not definitive regarding the impact on colorectal cancer recurrence, the convergence of clinical observations and biology provides a compelling justification to test-hypothesis-driven interventions in prospective randomized clinical trials," write the experts.
Meyerhardt added: "In light of our and other's research, we theorize that factors including a high glycaemic load may stimulate the body's production of insulin.
"That, in turn, may increase the proliferation of cells and prevent the natural cell-death process in cancer cells that have metastasized from their original site."
Source: Journal of the National Cancer Institute
Published online ahead of print, doi: 10.1093/jnci/djs399
“Dietary Glycemic Load and Cancer Recurrence and Survival in Patients with Stage III Colon Cancer: Findings From CALGB 89803”
Authors: Jeffrey A. Meyerhardt, Kaori Sato, Donna Niedzwiecki, Cynthia Ye, et al