Dietary Pattern at 18-Month Post-Diagnosis and Outcomes of Breast Cancer Among Chinese Women with Early-Stage Breast Cancer

Background: Evidence of the association between dietary pattern and outcomes of breast cancer was limited in Asian women, including Chinese.

Patients and methods: A prospective cohort study was initiated among Chinese breast cancer patients to investigate lifestyle habits and outcomes of breast cancer. At each follow-up, validated food frequency questionnaires (FFQ) were used to assess patients' dietary intake. This study included 1226 patients with invasive early-stage breast cancer with detailed data at 18-month follow-up after cancer diagnosis. Factor analysis was used to derive dietary patterns, whereby two dietary patterns were identified. Cox proportional hazards models were used to investigate associations between dietary patterns and time to outcome, including breast cancer recurrence, overall mortality and breast cancer-specific mortality.

Results: With a median follow-up time of 54.1 months, 165 patients had breast cancer recurrence and 98 deaths occurred. Two dietary patterns were identified: "Western dietary pattern" characterized by high intake of refined grains and cakes, red and processed meat and oil; "healthy dietary pattern" characterized by high consumption of vegetables and fruits. Participants in the highest tertile of "Western dietary pattern" did not have a higher risk of breast cancer recurrence (P _trend = 0.89), overall mortality (P _trend = 0.48) and breast cancer-specific mortality (P _trend = 0.75). Similarly, a null association existed between "healthy dietary pattern" and outcomes of breast cancer.

Conclusion: Neither dietary pattern was associated with risk of breast cancer recurrence, all-causes death or death from breast cancer. Prospective follow-up is still needed to further confirm the association between specific dietary pattern and outcomes of breast cancer.