It's an unfortunate fact that even successful cancer treatment can leave lasting scars. Surgeries are sometimes needed to remove tumors, skin can be permanently damaged from radiation therapy and powerful chemotherapy drugs can wreak havoc throughout the body.
One of the least understood lasting effects, however, is a cognitive deficit that some survivors describe as "chemobrain." The difficulties they experience in focusing and remembering are attributed to the neurotoxic effects of chemotherapy. But it's not been clear whether some drugs are worse than others in this regard.
Now Stanford oncologist Douglas Blayney, MD, and former Stanford faculty member Shelli Kesler, PhD, have published a study in JAMA Oncology assessing cognitive defects in a group of 62 breast cancer patients treated between 2008 and 2014. About one-third of the patients had received a class of chemotherapy drugs that are anthracycline-based, like doxorubicin; one-third received other chemotherapy drugs that were non-anthracycline-based; and the remainder received no chemotherapy at all.
As Blayney explained in an email to me:
Chemotherapy for breast cancer is often associated with cognitive problems in patients. However, it is unclear whether certain treatment regimens are associated with greater cognitive difficulties than others. In a small study, we showed that women treated with anthracycline-based chemotherapy had lower verbal memory, including immediate recall and delayed recall, compared with non-anthracycline chemotherapy treated breast cancer patients, and breast cancer patients not treated with chemotherapy.
Although their results are intriguing, Blayney cautions that the study was relatively small and it's too soon to start ruling out one type of chemotherapy over another. But it's important to begin these types of analyses. He writes:
Patient-reported outcomes of cognitive dysfunction and psychological distress were elevated in both groups of women treated with chemotherapy compared with patients treated without chemotherapy. Our study is hypothesis generating, involves small numbers of patients, there is no dose-response information available, and it is way too soon to abandon doxorubicin adjuvant treatment, which remains a valuable chemotherapeutic agent. We are currently enrolling in a larger, longitudinal study of women measuring cognitive functioning before any treatment, after completion of systemic treatment, and one year later.
Previously: Wellness after cancer: Stanford opens clinic to address survivors' needs, A look at stem cells and “chemobrain" and Stanford study shows effects of chemotherapy and breast cancer on brain function
Image by Steve Snodgrass