Colorectal cancer survival: what is the role of diet?

ColoursOfHealth_AlexProimosDiet is thought to play a key role in cancer susceptibility, with more than half of colorectal cancers (CRC) thought to be potentially preventable through changes in lifestyle factors such as diet and physical activity; however, the subsequent role of diet on CRC survival is unclear. With an estimated 244,000 CRC survivors in the United Kingdom alone, this is an urgent area of research. Scientific research has helped to identify some of the specific ways through which diet might be related to development of CRC. For example, dietary fibre helps maintain bowel regularity, thus possibly reducing exposure to potentially cancer-causing compounds in bodily waste. It is possible that dietary habits after CRC diagnosis may also be related to health outcomes, such as a recurrence of the cancer; however, there has been relatively little research undertaken on this topic. 

Large cohort studies such as the European Prospective Investigation into Cancer and Nutrition (EPIC) study provide opportunities to examine dietary intake (data collected from all participants when they first joined EPIC, prior to CRC diagnosis) in relation to mortality among those who developed CRC after joining the study. One team of investigators explored mortality among 3,292 EPIC participants diagnosed with CRC relative to adherence to the World Cancer Research Fund/American Institute of Cancer Research (WCRF/AICR) recommendations for cancer prevention (including dietary factors, activity, and obesity), as these recommendations have been previously associated with lower risk of developing CRC . There was a significant pattern of lower mortality among CRC survivors with greater adherence to the recommendations prior to their cancer diagnosis, and those with the highest concordance had 30% lower risk of mortality than those with the lowest adherence. The elements of the WCRF/AICR recommendations that were most strongly associated with improved survival were those related to healthy body weight and consumption of plant based foods (both prior to diagnosis). However, it’s too early to assume that all dietary factors associated with CRC incidence are also related to with CRC survival: another EPIC analysis reported no association between CRC survival and intake of dairy products or calcium, dietary factors that are associated with lower risk of developing CRC.

It is clear that more research is needed to understand the role that diet might play in health outcomes among CRC survivors. Organizations such as World Cancer Research Fund have identified the health of cancer survivors, both in terms of preventing cancer recurrence and improving general health, as a focus for research funding, so it may not be long before further evidence becomes available.

Heather Ward

Heather Ward

Heather Ward is a Research Fellow in the Department of Epidemiology and Biostatistics at Imperial College London. She is a nutritional epidemiologist, with an interest in a variety of modifiable diet and lifestyle exposures in relation to chronic disease (primarily cancer).

Research Interests: Nutrition, physical activity, obesity, cancer, cancer survival, dementia
Heather Ward

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