For many years, breast cancer patients have reported experiencing difficulties with memory, concentration and other cognitive functions following cancer treatment. Whether this mental "fogginess" is psychosomatic or reflects underlying changes in brain function has been a bone of contention among scientists and physicians.
Now, a new study led by Dr. Patricia Ganz, director of cancer prevention and control research at UCLA's Jonsson Comprehensive Cancer Center, demonstrates a significant correlation between poorer performance on neuropsychological tests and memory complaints in post-treatment, early-stage breast cancer patients - particularly those who have undergone combined chemotherapy and radiation.
"The study is one of the first to show that such patient-reported cognitive difficulties - often referred to as 'chemo brain' in those who have had chemotherapy - can be associated with neuropsychological test performance," said Ganz, who is also a professor of health policy and management at UCLA's Fielding School of Public Health and a professor of medicine at the David Geffen School of Medicine at UCLA.
The study was published April 18 in the online edition of the Journal of the National Cancer Institute and will appear in an upcoming print edition of the journal.
Ganz and her colleagues looked at 189 breast cancer patients, who enrolled in the study about one month after completing their initial breast cancer treatments and before beginning endocrine hormone-replacement therapy (70 percent planned to undergo hormone therapy). Two-thirds of the women had had breast-conserving surgery, more than half had received chemotherapy, and three-quarters had undergone radiation therapy. The average age of study participants was 52.
Because cognitive complaints following cancer treatment have often been associated with anxiety and depressive symptoms, limiting confidence that "chemo brain" and similar difficulties reflect a cancer treatment toxicity, the researchers excluded women with serious depressive symptoms. They also took careful account of the cancer treatments used and whether or not menopause and hormonal changes could be influencing the cognitive complaints. A sample of age-matched healthy women who did not have breast cancer was used as a control group.
The researchers provided a self-reporting questionnaire to the women and found that those with breast cancer reported, on the whole, more severe complaints than normal; 23.3 percent of these patients had higher complaints about their memory, and 19 percent reported higher complaints about higher-level cognition (problem-solving, reasoning, etc.). Significantly, those breast cancer patients who reported more severe memory and higher-level cognition problems were more likely to have undergone both chemotherapy and radiation.