Many patients report changes in their cognitive function related to their illness and the treatments they receive that adversely impact aspects of occupational, social, emotional or other areas of important functioning. Changes in attention, memory, thinking speed, problem-solving and other cognitive functions have been termed "chemobrain" or "chemofog" by patients.  Studies of patients with non-central nervous system cancer have demonstrated that approximately one-third of patients exhibit cognitive dysfunction prior to the administration of systemic anti-cancer treatments. Systemic anti-cancer therapy (e.g., chemotherapy) is also associated with worsening cognitive function in a subset (ranging from 0-61%) of patients The exact percentage of patients that are vulnerable to these adverse side-effects is unknown and is probably related to the type and dose of treatment a patient receives. For some patients, these alterations in cognitive function appear transient and may recover after treatment has ceased. Other patients may experience long-lasting changes in cognitive function that may benefit from supportive medical care and lifestyle modifications.

The research conducted by the ICCTF members and others around the world is devoted to increasing our understanding of the incidence, severity, individual risk factors, and causes of cognitive and behavioral dysfunction, as well as investigations into ways to prevent and intervene against these adverse symptoms.