Cancer treatments such as chemotherapy and radiation work by damaging the DNA of cancer cells, thereby killing them. Unfortunately, it is impossible for these treatments to target only the diseased cells; therefore, surrounding healthy cells also suffer from DNA damage as a result of treatment. This DNA damage to healthy cells could have dire consequences. Findings from a study published in Cancer reveal that certain treatments for breast cancer increase patients' exposure to toxicities that may result in cognitive decline.
In 94 women between the ages of 36 to 69 who had been treated for early-stage breast cancer three to six years prior to the study, blood samples were taken to determine the extent of damage caused to biological aging markers such as leukocyte DNA, peripheral blood mononuclear cell (PBMC) telomere length, PBMC telomerase enzymatic activity, and inflammatory marker soluble tumor necrosis factor receptor II (sTNF-RII). To assess cognitive ability, executive function tests were administered.
The results indicated statistically significant evidence that higher DNA damage and lower telomerase activity correlated with lower decision-making task scores, after adjusting for possible confounding variables such as age, body mass index, race, years from treatment, and intelligence scores. Additionally, motor and speed test scores and lower telomerase activity were negatively correlated. However, no connection was found between sTNF-RII and telomere length and executive function scores.
According to the study's first author, Judith Carroll, PhD, member of Jonsson Comprehensive Cancer Center at the University of California, "These findings are important because they provide further information about what might be happening after cancer treatment that impacts cognitive decline in some individuals. This information can inform future research and may lead to new interventions to prevent these cognitive declines."
For More Information
Carroll J, Dyk K, Bower J, et al (2018). Cognitive performance in survivors of breast cancer and markers of biological aging. Cancer. [Epub ahead of print] DOI:10.1002/cncr.31777