Abstract Breast cancer is the most frequently diagnosed cancer among women. Breast cancer has shown survivorship rate improvements due to technology, early diagnosis and better treatments than before. As breast cancer survivors are living longer, there has been greater focus on understanding the side treatment effects. Women following mastectomy displayed several postural and biomechanical alterations. The major problem in women after mastectomy, besides upper limb dysfunction, are disorders in the trunk area, specially the thoracic kyphosis, which has an influence on the formation of functional disorders in the median part of the spine. The current research describes the postural and biomechanical alterations after mastectomy in breast cancer patients and review the evidence regarding the possible effect of external prosthesis in corporal biomechanics and functionality. Results showed a tendency of muscle imbalance and shoulder and neck asymmetry.