Expectations may influence side effects of breast cancer hormone therapy

By Kathryn Doyle (Reuters Health) - Side effects from taking tamoxifen for breast cancer may be worse if a patient expects they will be bad before therapy even begins, according to a study from Germany. Over a two-year period, women who expected more serious side effects before treatment started experienced almost twice as many symptoms as women who thought the therapy wouldn’t be too terrible. Since side effects can lead some women to stop taking their medication, patient expectations are an important factor for doctors to consider and possibly modify to improve treatment success, Yvonne Nestoriuc of the University Medical Center Hamburg-Eppendorf and her coauthors write in Annals of Oncology, August 22. They studied 111 women who had undergone surgery for hormone-receptor-positive breast cancer and were scheduled to start adjuvant endocrine treatment. The women answered questions about their expectations of the hormone therapy and were reassessed for side effects three months later and again at 24 months. Most women expected mild side-effects from the therapy, 30 percent said they expected more severe side-effects and less than 10 percent did not expect any. At the two-year mark, 87 percent of women who did not expect severe side effects had stayed with the therapy, compared to 69 percent of women who had expected more severe side-effects. More than half of the women experienced joint pain and weight gain and about half had hot flashes while on hormonal therapy. One third to nearly half also reported back pain, breast scar tissue pain, breathing problems and dizziness, palpitations and circulation problems, which are not among listed side effects of the therapy. Women with worse expectations reported an average of 10 symptoms while those with less negative expectations reported an average of six. After researchers adjusted for age, menopausal status, depression, anxiety and concurrent health conditions, they found that expectations were a strong independent predictor of symptom severity, particularly at the three-month mark. In a “nocebo” response, patients attribute other symptoms unrelated to treatment all to one cause, in this case, hormonal therapy, said Dr. Paul Enck of University Hospital Tubingen, Germany, who was not part of the study. “There is no indication that poor expectations are associated with poor health conditions in general, negative expectations are a matter of personality (anxiety-driven for instance), and that can affect people with poor as well as with good health conditions,” Enck told Reuters Health by email. Mental outlook might affect the experience of recovering from a range of health conditions, like a broken leg or asthma, diabetes or Crohn’s disease, he said. Doctors need to be aware that expectations determine outcome, and speak with patients to determine if their expectations may be too positive or too negative, he said. “I suspect that there is a causal relationship based on experiences in our lab,” said Dr. Luana Colloca of the University of Maryland in Baltimore, who was not part of the new research. “We are understanding now that expectations are not merely a score on a questionnaire, they trigger a cascade of events in our brain,” Colloca told Reuters Health. “Unfortunately clinicians and providers are not so aware about these influences.”