The memory and thinking problems experienced by cancer survivors, known as "chemo brain" or "chemo fog," are not just the result of chemotherapy treatment, they may start as tumors form and develop, suggests a study led by Dr. Gordon Winocur, Psychology professor at Trent.
Professor Winocur and his team found that female mice with a form of breast cancer demonstrated impaired performance on learning and memory tests before chemotherapy drugs were administered, according to recent findings published in the journal Neuroscience.
"Our work isolated that the cancer is responsible for some of the memory and thinking complaints experienced by cancer survivors, and that drug therapy adds to the problem," says Prof. Gordon Winocur, senior scientist at Baycrest's Rotman Research Institute and psychology professor at Trent University and the University of Toronto. "Both factors independently affect brain function in different ways, which can lead to the development of other psychological disturbances, such as anxiety and depression."
After chemotherapy, as many as 65 per cent of patients with breast cancer report memory lapses, difficulty concentrating, taking longer to complete tasks and difficulty multitasking. Patients with other types of cancer have reported similar problems.
"Our research found that the cancer and chemotherapy cause three separate, but related brain changes," says Prof. Winocur. "Understanding the nature of the cognitive impairment and the underlying biological mechanisms are essential to the development of an effective treatment for chemo brain. Our work shows that a targeted approach addressing all three issues is necessary to successfully treat the condition."
These findings lay the foundation for the development of targeted treatments. In previous work, Prof. Winocur demonstrated that drugs used to treat memory and thinking problems in Alzheimer's disease and physical exercise can offset chemo brain's impact. As next steps, Prof. Winocur will investigate these effects in cancer survivors who complain of chemo brain following chemotherapy.