<p>Cancer is a leading cause of death globally, including breast cancer, the most commonly diagnosed cancer, which significantly affects women’s mortality rates. Women exposed to hormones like estrogen from early menarche to delayed menopause may have a greater risk of breast cancer. The gut microbiota and its association with breast cancer are an emerging field of study. Any factors leading to dysbiosis of this gut microbiota could be a potential cause of breast cancer. Simultaneously, probiotics, postbiotics, and next-generation probiotics (NGPs) have emerged as promising supplements in cancer management due to their potential to modulate the gut microbiota and augment immune responses. Thus, these biotherapeutics contribute a greater insight into immunotherapies and the modulation of the tumor microenvironment. The ability to prevent dysbiosis and maintain a healthy gut microbial population can assist in treating breast cancer. Although they show promise, more holistic research is necessary to fully comprehend their mechanisms of action, safety, and clinical effectiveness in humans. This review highlights the crucial role of biotherapeutics in enhancing breast cancer treatments by examining the significance of gut microbiota in cancer progression and control, thus underscoring the necessity for continued research in this area.</p>