Advances in screening and treatment of breast cancer have led to reductions in breast cancer recurrence and mortality. However, systemic therapies can cause long-term and late effects that negatively impact the quality of life of patients with breast cancer. It is important for patients to be aware of the potential risks, and for providers to be knowledgeable about symptom management options. For example, taxane chemotherapies reduce the risk of disease recurrence but can cause long-lasting neuropathy that interferes with activities of daily living. Unfortunately, few effective interventions for preventing or treating neuropathy have thus far been identified. Similarly, endocrine therapies significantly reduce the risk of recurrence of hormone receptor positive breast cancer. However, tamoxifen and the aromatase inhibitors can cause menopausal symptoms and arthralgias that affect survivors of breast cancer of all ages. Interventions that can effectively treat these symptoms in some, but not all, patients have been identified. In this educational session, prevention and treatment approaches for key long-term and late effects in patients with breast cancer will be discussed. Citation Format: N Henry. Toxicities of breast cancer treatment [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr SP059.