Nov 10, 2014
By Shira Klapper, Senior Writer/Editor
Numerous studies have shown chemotherapy to be associated with cognitive difficulties among women being treated for breast cancer. However, few studies have looked at the cognitive effects of another common breast cancer treatment—endocrine therapy. Endocrine therapy, which is taken by 60-70% of women with breast cancer, includes drugs such as aromatase inhibitors and tamoxifen and acts to block hormones that promote the growth of breast cancer cells.
Now, a new study in the Journal of Clinical Oncology (JCO) finds that women who received endocrine therapy following initial breast cancer treatments—surgery, with or without radiation or chemotherapy —were significantly more likely to report greater problems in a specific cognitive domain: word and phrase retrieval, compared to women who did not start endocrine therapy. The increased difficulties in this domain, which is called, “language and communication,” was also significantly associated with poorer scores in psychomotor function as tested by a neuropsychological test. The study, “Cognitive Function After the Initiation of Adjuvant Endocrine Therapy in Early-Stage Breast Cancer: An Observational Cohort Study,” was published online, ahead of print, September 29, 2014.
According to first author Patricia Ganz, MD, FASCO, “We were able to show that women who received endocrine therapy had increased complaints in language and communication. That’s the subjective evidence. But then we were also able to show through the objective evidence of the neuropsychological testing that the speed of processing was slower in the domain of psychomotor function.”
According to Dr. Ganz, these findings have clinical significance in that they enable doctors to validate the complaints of women who may come into clinic reporting ongoing challenges in remembering and retrieving words after starting endocrine therapy for breast cancer.
“If a patient comes back to see you three months after starting their tamoxifen or aromatase inhibitor, and they’re saying, ‘I’m having some difficulty finding words, I didn't have this problem before,” we can say to the patient—‘you know, that could be from the medication you’re taking. Let’s just see how you do with it. Maybe it will get better over time, let’s watch it,’” said Dr. Ganz. “That, I think, is very helpful to patients because if you do not validate their reports, they may stop the endocrine therapy without you knowing about it.”
Endocrine therapy compared to no endocrine therapy
To answer the research question—is endocrine therapy associated with increased complaints in cognitive function and lower scores on the neuropsychological test?—the researchers looked at 173 participants from the Mind Body Study cohort who were between 21 and 65 years old and who had completed initial treatments for stage 0, I, II, III, or IIIA breast cancer (surgery, with or without radiation or chemotherapy) but had not yet started endocrine therapy.
All patients met with researchers before starting endocrine therapy and then at the six and 12 month time point. At each time point, patients filled out a self-report questionnaire about their cognitive function and completed the 90-minute neuropsychological testing. Study participants were also assessed for level of depression and quality of life since these factors may be independently associated with cognitive complaints.
The study also asked women about past hormonal exposures and changes in current menstrual status to examine whether or not these factors played any role in cognitive changes after breast cancer treatments.
“We asked women whether they stopped menstruating with the chemotherapy because we thought that changes in their menstrual and hormonal status might create troubling cognitive issues for some women,” said Dr. Ganz. “We know that as women go through the menopause normally, they often have trouble finding the right words and are slower at remembering words.”
To carry out the analysis, the researchers divided the data gathered during the first and sixth month time point into two groups: One that included data on women who started endocrine therapy after the first time point and one that included data on women who had not. When the two groups were compared, the researchers found that those who received endocrine therapy were significantly more likely to report higher complaints in language and communication at the six-month assessment. The study also found that the cognitive difficulties reported with endocrine therapy were made significantly worse if the patient had a history of prior hormonal therapy for menopause. Depression was not significantly associated with increased language and communication complaints as a result of endocrine therapy. Furthermore, a change in menstrual status was not significantly associated with increased language and communication complaints as a result of prior chemotherapy treatment.
Interventions for cognitive complaints
According to Dr. Ganz, this research can lay the groundwork for additional studies on endocrine therapy and cognitive complaints—and may ultimately lead to interventions to help women manage these complaints.
“We, and others, have been working on interventions to try and help women deal with some of the after-effects of cancer treatment,” said Dr. Ganz. “And, it’s possible that women who are very troubled by this side effect and who are not getting better could benefit from some of those interventions.”
Patricia Ganz, MD, FASCO is a medical oncologist and the Leader of Patients and Survivors Program Area at the Jonsson Comprehensive Cancer Center at the University of California, Los Angeles (UCLA), where she also directs the Center for Cancer Prevention and Control Research. She is also a professor of Health Policy and Management at the UCLA Fielding School of Public Health. Dr.Ganz has been an ASCO member since 1980 and is currently a member of multiple ASCO Committees, including the Palliative Care in Oncology Symposium Planning Committee, the Fatigue Guideline Committee, and the Cancer Survivorship Committee. In addition, Dr. Ganz served as Chair of several ASCO committees in the past, including Publications, Quality of Care, and Personnel. She has also served as Associate Editor of JCO and on the ASCO Board of Directors. In 2008, Dr. Ganz received the American Cancer Society Award and was awarded the status of a Fellow of the American Society of Clinical Oncology (FASCO). She was also awarded the Conquer Cancer Foundation 2010 Comparative Effectiveness Research Professorship in Breast Cancer.*
*The Conquer Cancer Foundation has a strong track record—spanning more than three decades—of funding the brightest minds in clinical and translational research, with the ultimate goal of improving cancer care for patients in the U.S. and abroad. Visit ConquerCancerFoundation.org to learn more or to donate.
Read the abstract of the original JCO article
View the PDF of the original JCO article.
Ganz PA, Petersen L, Castellon SA, et al. cognitive function after the initiation of adjuvant endocrine therapy in early-stage breast cancer: an observational cohort study. J Clin Oncol. Epub 2014 Sep 29.
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@ 2014 American Society of Clinical Oncology