HealthDay News — Cruciferous vegetable intake was linked to decreased breast cancer mortality and recurrence rates among Chinese women, data presented at the annual meeting of the American Association for Cancer Research indicate.
“Breast cancer survivors can follow the general nutritional guidelines of eating vegetables daily and may consider increasing intake of cruciferous vegetables, such as greens, cabbage, cauliflower and broccoli, as part of a healthy diet,” Sarah J. Nechuta, MPH, PhD, a postdoctoral research fellow at Vanderbilt University in Nashville, Tenn., said in a press release.
She and colleagues prospectively enrolled 4,886 Chinese women aged 20 to 75 years diagnosed with stage I to IV breast cancer from 2002 to 2006 to participate in the Shanghai Breast Cancer Survival Study. Cruciferous vegetable intake was assessed at baseline, 18 months and 36 months. After a median follow-up of 5.2 years, the researchers identified 587 deaths (496 breast cancer-related) and 615 cases of recurrence.
The researchers found that eating cruciferous vegetables during the first 36 months after breast cancer diagnosis reduced the risk for total mortality, breast cancer-specific mortality and recurrence in a dose–response pattern, after adjusting for sociodemographic, clinical and lifestyle factors.
Across increasing quartiles of cruciferous vegetable consumption, total mortality risk decreased 27% to 62%, breast cancer-specific mortality risk decreased 22% to 62%, and recurrence risk decreased 21% to 35%.
Compared with the lowest quartile of intake, across increasing quartiles, the multivariable hazard ratios were 0.73, 0.51, and 0.38 for total mortality; 0.78, 0.53, and 0.38 for breast cancer-specific mortality; and 0.79, 0.71, and 0.65 for recurrence. After exclusion of the first year of observation, the associations persisted, although the correlation for recurrence was no longer significant.
However, cruciferous vegetable consumption habits differ between China and the United States, Nechuta noted, suggesting that the results may not be generalizable to U.S. breast cancer survivors. Commonly consumed cruciferous vegetables in China include turnips, cabbage or bok choy and greens, whereas in the U.S. and other Western countries, cruciferous vegetables consists mostly of broccoli and brussel sprouts.
“The level of bioactive compounds such as isothiocyanates and indoles, proposed to play a role in the anticancer effects of cruciferous vegetables, depend on both the amount and type of cruciferous vegetables consumed,” Nechuta said.
Future studies should look at the effects of these biological compounds to better understand the association of cruciferous vegetable intake with breast cancer outcomes.