Breast cancer is a heterogeneous disease with varying subtypes, prognoses, and treatment responses. Cruciferous vegetables have shown promise in reducing breast cancer risk. This review discusses (<i>a</i>) the efficacy of sulforaphane (SFN) and indole-3-carbinol (I3C)/3,3'-diindolylmethane (DIM) on breast cancer risk, prognosis, and treatment outcomes in recent human studies through 2024; (<i>b</i>) preclinical studies (2018-2024) that evaluate the efficacy and synergism of SFN, DIM, and other phytochemicals with conventional breast cancer treatments as promising combination therapy strategies for validation in future clinical trials; and (<i>c</i>) the role of the microbiome in breast cancer and the interaction between interindividual variations in gut microbiome and glucosinolate metabolism that could modify the benefits of cruciferous vegetable consumption and breast cancer treatment efficacy. Integrating cruciferous vegetables and their bioactive compounds in light of an individual's microbiome profile as a complementary approach alongside standard treatments is a promising strategy in breast cancer care.
