As the child of Holocaust survivors, I do not have many relatives. My half-sister, grandparents, multiple aunts and uncles were all killed in Europe and I am an only child. So my closest relatives are my first cousins—you know the drill. One of them, my cousin Leo Weinberg, told me over Thanksgiving that he reads my column but only really likes the articles when I write something about our family. So let me write today how proud I am that he is making aliyah in the coming month or two to live in Jerusalem. I hope that this gets him to read today’s article.

Chemo brain is a term that is sometimes used to refer to changes in a cancer patient’s memory, concentration or ability to think clearly that are brought on by chemotherapy. It can last for months even after the cessation of therapy.

It has been reported most commonly in women who are undergoing chemotherapy for breast cancer and also in patients with central nervous system tumors. Thus, the drugs utilized for these tumors are the ones most often implicated with regard to chemo brain as well—Adriamycin (doxorubicin), Cytoxan (cyclophosphamide) or Taxol (paclitaxel). Nonetheless, it is daunting to realize that in surveys up to 75% of patients report cognitive symptoms during active treatment, and that these symptoms may continue for weeks and months afterwards.

Of course, these issues do not occur in a vacuum. Psychological problems in cancer patients interact with the utilization of the chemotherapy drugs to lead to these symptoms. Stress, anxiety, depression and sleep problems can all overlay the pharmacologic issues. There is, in addition, some evidence that some chemotherapy drugs can cross the blood-brain barrier and kill brain stem cells.

Clearly many cancer patients are also beset by depression, and many of these symptoms are similar between the two conditions. Thus, it may not be easy to distinguish depression from what we refer to as chemo brain.

One observation, reported now in multiple studies, is that these problems are not limited to patients treated for breast and central nervous system or brain tumors, but that cognitive problems may occur across a wide spectrum of malignancies. These may include lymphoma, colorectal cancer, head and neck cancer, sarcoma and others. Several surveys in Europe and North America have replicated such findings.

Indeed, the reason I am writing this article now is that I recently came across an interesting large study conducted at the Princess Margaret Cancer Centre at the University of Toronto. They administered a computerized survey instrument to all cancer patients treated there. In a paper that was just published in JAMA Network Open, they reported on the responses of 5,078 patients to the survey’s questions regarding their cognitive symptoms between 2013 and 2019. The respondents were 55% female, and covered a spectrum of 12 malignancies that were metastatic, including breast, hematologic, gynecologic, head and neck, gastrointestinal, genitourinary, lung, brain, sarcoma, thyroid, melanoma and other cancers.

Overall, cognitive symptoms were reported by 3,480 (68.5%) of the patients; as in the other studies we have cited, the highest proportions were for breast cancer (78.4%) and brain/CNS tumors (86.5%). Generally speaking, higher rates were found for females as compared to males, as well as for those who reported concomitant depression. Those patients who were closer in time to the initial diagnosis also tended to have higher rates of cognitive impairment. It is also important to note that cognitive symptoms were very often accompanied by other symptoms, such as shortness of breath or fatigue. They were also indicative of a higher risk of recurrence of the tumor.

While these cognitive symptoms may occur in conjunction with any type of therapy, they are certainly most frequent and most severe in the setting of chemotherapy. Interventions, such as social support, need to be designed and implemented to anticipate such problems and to prevent their occurrence. Studies have demonstrated that exercise programs may prevent or reduce the cognitive problems precipitated by systemic chemotherapy and thus this may be a useful preventive recommendation. Accompaniment to clinic visits by friends or family members would also be measures that would be useful for the reduction of these problems.

As a sidelight, it does raise the issue of automobile driving by patients who are initially undergoing chemotherapy. At least until it is clear that the patient will not suffer significant cognitive problems, it may be worthwhile to be accompanied by a driver.

It is also of interest that significant effort has gone into mapping changes in the brain in conjunction with chemo brain with the use of neuro-imaging. It does seem like MRI can frequently map changes in the white matter of the brain in patients with severe symptoms of chemo brain. Similarly, PET scans also show brain changes under these circumstances, but the changes are not uniformly consistent. Nonetheless, it is important to appreciate that chemo brain does appear to reflect true physiologic effects of the drugs and treatments.

Alfred I. Neugut, MD, PhD, is a medical oncologist and cancer epidemiologist at Columbia University Irving Medical Center/New York Presbyterian and Mailman School of Public Health in New York. Email: [email protected].

 This article is for educational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment, and does not constitute medical or other professional advice. Always seek the advice of your qualified health provider with any questions you may have regarding a medical condition or treatment.