"Chemo brain" is the colloquial term that millions of cancer patients use to describe a constellation of cognitive symptoms that follow chemotherapy: difficulty concentrating, memory lapses, mental fogginess, slowed processing speed, and trouble finding words. It affects up to 80 percent of people receiving chemotherapy, and while it sometimes improves after treatment ends, for many cancer survivors it persists for months to years, affecting their ability to return to work, drive safely, manage finances, and maintain the independence that cancer treatment was supposed to preserve.
The neurobiological mechanisms behind chemo brain are increasingly understood. Chemotherapy agents damage neural tissue both directly and through inflammatory cascades, oxidative stress, reduced cerebral blood flow, and disruption of the hypothalamic-pituitary axis. The result is measurable changes in brain structure and function — detectable on neuroimaging and cognitive testing — that correlate with the subjective experience patients describe.
