Patients already diagnosed with colorectal cancer do not face an increased risk of either disease recurrence or death if they eat red or processed meats, suggests a new analysis of prospective US trial data.
“Although our study has limitations, these findings can potentially inform patient counseling and the development of dietary guidelines specific for cancer survivors,” say the authors.
The results suggest that it is okay for patients with colorectal cancer to eat these foodstuffs, which is in direct contrast to current recommendations.
At present, cancer survivors are recommended by both the American Cancer Society and American Institute for Cancer Research/World Cancer Research Fund to limit their intake of red and processed meats.
This is based on the known association between red and processed meat intake and an increased risk of colorectal cancer. This association was confirmed yet again just recently, as reported by Medscape Medical News, but it comes from studies in the general population.
In this latest study, the researchers looked specifically at individuals who already had been diagnosed with colorectal cancer to determine whether the recommendation to avoid red and processed meats is warranted.
The research was published by JAMA Network Open on February 22.
Erin L. Van Blarigan, ScD, Department of Epidemiology and Biostatistics, University of California, San Francisco, identified 1011 patients with stage III colorectal cancers from the Cancer and Leukemia Group B trial. Median age at enrollment was 60 years; 44% of participants were women, and 89% were White.
Participants completed a validated food frequency questionnaire approximately 3 months after diagnosis and again 6 months after they had completed treatment, or around 15 months after diagnosis.
As well as red and processed meat intake, the researchers assessed health behaviors such as smoking history, aspirin use, physical activity, and use of vitamins and mineral supplements.
Patients with the highest consumption of red meat were more likely than other participants to be male and White, to have been diagnosed with stage T3 or T4 cancer, to have poorly or undifferentiated disease, and to have a higher median body mass index (BMI).
Those with the highest consumption of processed meat were more likely than other people to be male and Black, to be current smokers, to have a higher median BMI, and to have been diagnosed with stage T3 or T4 disease.
Over a median follow-up of 6.6 years, there were 81 colorectal cancer recurrences and 305 deaths.
Multivariate analysis showed that there was no association between intake of red or processed meat after colon cancer diagnosis and risk of disease recurrence or mortality.
The hazard ratio for risk of recurrence in the highest vs the lowest quartiles of red meat consumption was 0.84, while that for processed meat was 1.05.
The risk of all-cause mortality was similar, at a hazard ratio of 0.71 for the highest vs the lowest quartiles of red meat consumption and a hazard ratio of 1.04 for processed meat.
The authors note that their study was observational and examined self-reported behavior, so they “cannot rule out the possibility of unmeasured or residual confounding.”
Moreover, they caution that their results “may not apply” to patients with stage I–II or IV colorectal cancer, and the available data did not offer information on “prediagnostic meat intake or…meat cooking practices.”
The research was supported by the National Cancer Institute of the National Institutes of Health. Jeffrey A. Meyerhardt’s research is supported by the Douglas Gray Woodruff Chair fund, the Guo Shu Shi Fund, the Anonymous Family Fund for Innovations in Colorectal Cancer, Project P fund, and the George Stone Family Foundation. Van Blarigan has disclosed no relevant financial relationships. Meyerhardt has relationships with Boston Biomedical, COTA Healthcare, Merck, and Taiho Pharmaceutical. Other authors report numerous relationships.
JAMA Netw Open. Published online February 22, 2022. Full text
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