Cancer is characterized by the disordered growth of cells that have high capacity of invasion to the tissues and organs. One of the types of tumour that has national incidence and high mortality is breast cancer. Studies show that in addition to hereditary factors, lifestyle and environmental factors, there are factors related to emotional distress (mourning), which interfere with the development of breast cancer. Thus, it is necessary to investigate if the experience of mourning can trigger the appearance of the tumour. For this, an integrative review was performed to verify the existence of the relationship between mourning and development of breast cancer, which presented contradictory results. Methodological errors and lack of access to important information, such as alcohol and tobacco use, were pointed out as the main causes of the contradiction found. A possible mechanism involving cortisol release has been proposed, but more research is needed to make it clear whether the association between mourning and breast cancer really exists, and by what path.