Rationale:~Although information about their treatment and its side-effects is requested by cancer patients, is vital for informed decision making and can positively impact patients' health outcomes and illness perceptions, this kind of information can also adversely impact perceived cognitive symptoms and cognitive test performance. Previous studies have shown that informing cancer patients about potential chemotherapy-related cognitive symptoms may negatively affect perceived cognitive symptoms and verbal memory performance. A multicenter, randomized study in newly diagnosed breast cancer patients receiving (neo) adjuvant chemotherapy was performed to evaluate this Adverse Information Effect (AIE) over time and investigated whether inviting patients to self-affirm can reduce such AIEs on perceived cognitive symptoms and cognitive test performance.~Main objectives and hypotheses:~The overall aim of the study was to investigate the occurrence and duration of AIEs on the perceived frequency of cognitive symptoms, the perceived severity of cognitive symptoms and cognitive performance in breast cancer patients, and to examine ways to reduce such AIEs. First, evaluated the effect of providing breast cancer patients with additional factual written information about potential chemotherapy-related cognitive symptoms before chemotherapy-initiation on perceived cognitive symptoms and cognitive performance was evaluated, and the duration of such effects was assessed. Building on previous findings that breast cancer patients showed an increase in perceived cognitive symptoms and a decrease in verbal memory performance after receiving cognitive side-effect information, it was hypothesized that communicating about potential chemotherapy-related cognitive symptoms will result in AIEs, and it was explored to what extent these AIEs persist over time. Second, this study aimed to translate the beneficial effects of self-affirmation to the oncology domain, and examined the efficacy of a text-integrated self-affirmation intervention in reducing the impact of AIEs on perceived cognitive symptoms and cognitive performance in breast cancer patients when communicating about chemotherapy-related cognitive symptoms. It was hypothesized that a textual self-affirmation intervention would reduce AIEs in breast cancer patients, building on evidence from health promotion and stereotype threat research outside the oncology domain that individuals' self-concepts can be affirmed via text-integrated health messages and that allowing individuals the opportunity for self-affirmation can reduce stereotype threat effects.~The main research questions were:~Does written information about potential chemotherapy-related cognitive symptoms presented only once before treatment-initiation affect short- and longer-term perceived cognitive symptoms (the perceived frequency and severity of cognitive symptoms) and cognitive performance (verbal memory performance, information processing speed, executive functioning) in newly diagnosed breast cancer patients scheduled for (neo) adjuvant chemotherapy?~Does providing newly diagnosed breast cancer patients with a text integrated self-affirmation intervention after being informed about potential chemotherapy-related cognitive symptoms reduce AIEs on short- and longer-term perceived cognitive symptoms and cognitive performance?~Study procedure and outcome measures:~Before (neo) adjuvant chemotherapy, 160 newly diagnosed breast cancer patients were randomly allocated to receive either standard information on side-effects (control condition), or standard information with additional information about chemotherapy-related cognitive symptoms (information condition), or standard and additional information with a subsequent self-affirmative text (information+SA condition; SA=self-affirmation). Online-questionnaires were completed before chemotherapy (baseline, T0), 6-months (T1) and 12-months (T2) later to measure the perceived frequency (MOS-cog) and severity (MDASI-cog) of cognitive symptoms. Patients also completed two online neuro-psychological tests (Trail Making Test; TMT, and 15 Words test) to measure verbal memory performance, information processing speed and executive functioning. Additionally, several potential underlying mechanisms and risk factors of AIEs were examined, such as cancer related distress and performance worries. Baseline-to-follow-up analyses were performed using a mixed-effects modeling approach to compare groups over time.
Previous cross-sectional studies have shown that informing cancer patients about potential chemotherapy-related cognitive symptoms may negatively affect perceived cognitive symptoms and verbal memory performance. A multicenter, randomized study in newly diagnosed breast cancer patients receiving (neo) adjuvant chemotherapy was performed to evaluate this Adverse Information Effect (AIE) over time and investigated whether inviting patients to self-affirm can reduce such AIEs on perceived cognitive symptoms and cognitive test performance.