Record ID: MS-N083 · Family: Nutrition and dietary patterns / survivorship · Clinical question: Is a Western dietary pattern after treatment associated with recurrence or survival in stage III colon cancer?
Evidence label: Adverse prospective observational association; the analysis supports a hypothesis, not proof that changing the pattern alters recurrence.
Evidence at a glance
- Benefit: No benefit claimed; higher Western-pattern scores were associated with worse outcomes.
- Certainty: Low-to-moderate for the association, low for causality.
- Risk: The concern is the overall pattern—refined grains, red and processed meat, sweets and fried foods—not a single ingredient.
- Cancer control: Changing the pattern has not been proven in a randomized trial to prevent recurrence.
What was studied
Researchers analyzed food-frequency questionnaires from 1,009 people with stage III colon cancer enrolled in CALGB 89803. A data-derived Western pattern was characterized by higher intake of red and processed meat, refined grains, sweets and desserts, and fried foods.
Participants were grouped into quintiles of pattern score. Diet was measured during and after adjuvant chemotherapy; it was not assigned.
What the results show
Compared with the lowest quintile, the highest Western-pattern quintile had adjusted HR 3.25 (95% CI 2.04–5.19) for recurrence or death, HR 2.85 (95% CI 1.75–4.63) for recurrence, and HR 2.32 (95% CI 1.36–3.96) for overall mortality. Median follow-up was 5.3 years from the first questionnaire.
The large relative associations are clinically important signals, but they remain vulnerable to confounding by activity, body weight, metabolic health, smoking, access to care and other diet features.
Important limits
- Dietary patterns were derived from self-reported data and were not randomized.
- Pattern labels depend on the specific questionnaire and statistical method.
- Illness can change appetite and food choice, creating reverse causation.
- The same CALGB cohort supports several related diet papers; they should not be counted as independent trials.
- Absolute risk for an individual cannot be calculated from these HRs alone.
Safety and practical context
A shift toward less processed food should still meet energy and protein needs. During bowel symptoms or weight loss, a temporary lower-fiber or higher-energy plan may be appropriate even if it differs from long-term prevention guidance.
Questions for the care team
- Is the goal long-term dietary quality or management of current treatment symptoms?
- Could bowel surgery, diarrhea or weight loss require a temporary modification?
- Which practical substitutions improve the whole pattern without causing restriction?
- How much of this evidence is association rather than intervention?
Sources checked
Funding and conflicts: The analysis was conducted within an NCI cooperative-group trial; full grant support and author disclosures are reported in the original paper.
Last literature search: October 20, 2026 · Record appraisal: October 20, 2026
Educational information only. This record is not a prescription and does not replace advice from the oncology team, registered dietitian or oncology pharmacist.
