Consuming a high amount of nuts may be related to better survival, particularly disease-free survival (DFS), in long-term breast cancer patients, according to a study recently published in Cancer Epidemiology. Although high nut consumption has long been linked with reduced mortality in the general population, its association with cancer outcomes among long-term breast cancer survivors was, so far, unknown.
This study examined the association between nut consumption (including peanuts and tree nuts) with overall survival (OS) and DFS among long-term breast cancer survivors (5-year post-diagnosis) from the Shanghai Breast Cancer Survival Study (SBCSS). Among 3,449 participants included in the final analysis, 3,148 were nut consumers. Using age as the timescale, Multivariable Cox proportional hazards models were employed to evaluate the hazard ratios (HRs) for OS and DFS events associated with nut intake.
During a median follow-up of 8.27 years post-dietary assessment, there were 374 deaths from any cause, including 252 deaths from breast cancer. At 10-year post-diagnosis, nut consumers had higher OS (93.7% vs 89.0%, p=0.003) and DFS (94.1% vs 86.2%, p<0.001) rates compared with non-consumers.
After multivariable adjustment, nut consumption was positively associated with OS (Ptrend=0.022) and DFS (Ptrend=0.003) following a dose-response pattern, with hazard ratios of 0.72 (95% CI: 0.52-1.05) for OS and 0.48 (95% CI: 0.31-0.73) for DFS for participants with higher median nut intake compared with non-consumers. Similar associations were observed for the consumption of peanuts, walnuts and other nuts. Stratified analyses showed that the associations were more evident among participants with a higher total energy intake for OS (Pinteraction=0.02) and among participants with early-stage (I-II) breast cancers for DFS (Pinteraction=0.04). The nut-DFS associations were not modified by estrogen receptor/progesterone receptor status or other known prognostic factors.
Diet has long been linked with breast cancer risk and survival. The results of this study suggest that nut consumption may be associated with better survival, particularly DFS, among long-term breast cancer survivors. Further studies could shed light on the convenience of emphasizing this diet in breast cancer survivor guidelines.