A new study has reported that breast cancer survivors may experience brain changes similar to those who have post traumatic stress disorder. The study was designed to investigate the effects of breast cancer treatment on the hippocampus, which is the part of the brain that is involved in memory formation, organization, and storage. Stress-related psychiatric disorders such as major depression and post traumatic stress disorder are associated with reduced hippocampus volume resulting in an episodic autobiographical memory deficit. However, breast cancer survivors who develop stress-related psychiatric disorders do not experience reduced hippocampus volume. This exception may be due to the fact that members of this population might already have a reduced hippocampus as a result of the cancer experience. The study included 16 breast cancer patients and 21 matched controls. The breast cancer patients had lived through a "standard experience of breast cancer" (breast cancer, standard treatment, in remission for 18 months) in the absence of any associated stress-related psychiatric or neurological disorder. To conduct the study, the authors scanned the brains of study participants and assessed their episodic autobiographical memory retrieval ability.

Breast cancer survivors were found to have both a significantly smaller hippocampus and a significant deficit in episodic autobiographical memory retrieval compared to cancer-free controls. The hippocampus atrophy was in the form of a smaller posterior hippocampus. It has been reported elsewhere that the posterior hippocampus is central to the protective function of fear conditioning. In the current study, the posterior hippocampus volume was found to be strongly associated with the ability to retrieve negative memories, as well as with the past experience of breast cancer (or not). The authors comment that the study results provide two main findings: (1) the identification of a new population (breast cancer survivors) with a specific reduction in posterior hippocampus volume that is independent of any psychiatric or neurological pathology; and (2) the intimate relation of the posterior hippocampus to the ability to retrieve episodic autobiographical memories. The authors conclude that these are significant findings as they represent the first evidence of considerable long-term effects of living through the experience of breast cancer and demonstrate very specific hippocampal atrophy with an associated functional deficit without any presence of psychiatric pathology.