Patients say they make mistakes when writing down numbers, forget names of people they know, and don’t remember the way to a familiar destination while en route, explained Janelsins. She’s an assistant professor of surgery, radiation oncology and neuroscience at the University of Rochester Medical Center and the Wilmot Cancer Institute in New York.
The researchers aimed “to really assess the problem [of chemo brain] in a very methodical and comprehensive way by including a nationwide sample,” Janelsins said.
Her team looked at 581 patients treated for breast cancer at multiple sites across the United States, comparing them with 364 healthy people without breast cancer. The average age was 53.
The researchers analyzed patients’ perceived impairment and also how others perceived the mental difficulties.
A month after chemo ended, 45 percent of patients reported a significant decline in so-called cognitive abilities, but only one in 10 in the comparison group did. The problems got better with time, but did not disappear.
After six months, 36 percent of patients still felt their mental ability had declined, compared to about 13 percent of the others.
Similar problems were experienced by women whether they received hormone therapy and/or radiation treatment after chemotherapy or chemo alone, the study found.
The researchers reported that younger women, black women and those with more anxiety and depression at the study start were more likely to have greater declines in brain functioning.
The researchers can’t say why chemotherapy drugs seem to lead to the fuzzy thinking. Nor can they say there’s a direct cause-and-effect relationship. They do know certain people are more vulnerable.
The important finding, Ganz said, is that some patients still had problems six months later.
While some researchers dismiss self-reporting as an untrustworthy research method, she disagreed. “If the patients tell you they are having [cognitive] difficulties, we have to acknowledge that and figure out a way to help,” she noted.
“The good news is, there are large numbers of women who get better,” Ganz said.