A new study on chemotherapy and its effect on the brain will be presented at the annual conference of the nation’s chief oncology group in Orlando. ASCO — the American Society of Clinical Oncology — has posted brief synopses of research, known as abstracts, online. (The meeting starts May 29. Late-breaking abstracts will be posted May 31.) The list is searchable by key word, and is good raw material for someone who wants to dive more deeply into the science of cancer and its treatment. At most conferences, new research is presented in several formats: as posters that are pinned up on boards in a large room, as an oral presentation on stage in front of an audience, or in a smaller panel or talk. The rigors of scientific research demand statistical analysis that may seem befuddling, even to those who took statistics in college. And researchers may use terms that seem arcane. But Google can be a powerful tool, making it relatively easy to search for definitions. Look for authoritative, official websites that have information vetted by doctors or researchers or science writers. For basics on cancer, or on study methodology, the National Cancer Institute website, found here, is clear and authoritative. Dig deep, and you can find an explanation for many medical and scientific terms.
One study being presented at the ASCO conference addresses cognitive functioning in breast cancer patients during and after chemotherapy. The study, done by researchers at the University of Rochester Medical Center in New York, was an outgrowth of another study of the antidepressant Paxil, which I blogged about here. Researchers looked at the changes that breast cancer patients reported over four cycles of chemotherapy, and then looked at how they were doing two years later. In all, 84 patients completed questionnaires about whether they experienced heavy headedness, muddled thoughts, difficulty thinking, trouble concentrating, or forgetfulness. (Patients filled out the questionnaires seven days after each treatment.) In all, 58 patients answered questions after all four cycles. Cognitive difficulties were highest after the first chemotherapy cycle, and were significantly improved by the third and fourth cycles.
But the researchers also found that there was an increase in cognitive difficulties AFTER the last cycle for a few patients — but not enough to be statistically significant. In other words, a very few patients found that their cognitive problems worsened after chemotherapy ended. Some patients reported improvements, and some reported no change.
The conclusion? The University of Rochester research suggests that cognitive difficulties related to cancer treatment are most pronounced after initial cycles of chemotherapy treatment, and that they improve during the treatment course. As always, this research is simply a guidepost along the pathway, one more dollop of information that may ultimately lead to a deepened understanding of chemobrain. Better testing is needed — paper and pencil tests that allow doctors and patients to track symptoms, paired with brain scans and tests that measure other biological processes.
“Further studies need to include objective neuropsychological examinations and biological correlates of cognitive functioning to understand the extend of cognitive decline due to chemotherapy,” the researchers say.