Breast cancer is still a lethal disease and the leading cause of death in women, undermining patients’ survival and quality of life. Modern techniques of surgery and radiotherapy allow for the obtaining of good results in terms of survival, however they cause long-term side effects that persist over time, such as lymphedema and neuropathy. Similarly, the advent of new therapies such as endocrine therapy revolutionized breast cancer outcomes, but side effects are still present even in years of follow-up after cure. Besides the side effects of medical and surgical therapy, breast cancer is a real disruption in patients’ lives considering quality of life-related aspects such as the distortion of body image, the psychological consequences of the diagnosis, and the impact on family dynamics. Therefore, the doctor-patient relationship is central to providing the best support both during treatment and afterwards. The aim of this review is to summarize the consequences of medical and surgical treatment on breast cancer patients and to emphasize the importance of early prevention of side effects to improve patients’ quality of life.