Dietary patterns and survival after breast cancer diagnosis

There is little prior study of major dietary patterns and breast cancer survival.

Patients included 2,619 Nurses' Health Study participants who were diagnosed with invasive breast cancer between 1982 and 1998 and completed a dietary questionnaire more than 1 year after diagnosis. Participants were followed through 2002 (median = 9 years). During follow-up, 414 patients died of any cause, 242 patients died of breast cancer, and 172 patients died from causes other than breast cancer. Women with in situ or metastatic disease at diagnosis were excluded. We used Cox proportional hazards models to evaluate prospective associations of prudent and Western dietary patterns assessed both before and after diagnosis with time to event after diagnosis.

In multivariate-adjusted analyses assessed after diagnosis, the Western and prudent dietary patterns were unrelated to all-cause or breast cancer mortality. However, compared with women with the lowest intake of the prudent dietary pattern, the relative risks (and 95% CIs) of death from causes other than breast cancer were 0.85 (95% CI, 0.53 to 1.35), 0.74 (95% CI, 0.45 to 1.21), 0.70 (95% CI, 0.42 to 1.17), and 0.54 (95% CI, 0.31 to 0.95; P = .03, from lowest to highest quintile of intake). In contrast, the Western dietary pattern was positively associated with this outcome (P = .04). Results for the assessment of dietary patterns before diagnosis were similar, except the prudent dietary pattern was unrelated to mortality.

A higher intake of the prudent pattern and a lower intake of the Western pattern may protect against mortality from causes unrelated to breast cancer.