Psychological predictors of chemotherapy-induced nausea in women with breast cancer: Expectancies and perceived susceptibility.

OBJECTIVE: Chemotherapy-induced nausea is challenging to predict and treat. Research indicates that pretreatment psychological variables including patients' perceptions of their susceptibility to nausea, expectancies of treatment-related nausea and nausea history (i.e., motion sickness, morning sickness and baseline levels of nausea) may aid in predicting nausea severity during chemotherapy. However, this research is dated and limited in quantity. We investigated whether psychological variables could improve prediction of nausea severity to inform interventions targeting chemotherapy-induced nausea. METHODS: In this secondary analysis, a subgroup of women receiving chemotherapy (for the first time) for breast cancer completed pretreatment measures: perceived nausea susceptibility, nausea expectancies, nausea history and baseline nausea. They rated subsequent nausea severity across 4-days, during treatment and posttreatment in a self-report diary. Structural Equation Modelling was used to explore associations. RESULTS: Across the women (N = 481), perceived nausea susceptibility predicted subsequent nausea severity (ß = 0.16), but nausea expectancies did not (ß = 0.05). Nausea history variables demonstrated small-moderate associations with perceived susceptibility (ß = 0.21-0.32) and negligible-small associations with nausea expectancies (ß = 0.07-0.14). CONCLUSION: Perceived nausea susceptibility appears to capture patients' nausea history, to a degree, and is related to nausea severity during treatment. This is an important variable to include in pretreatment prediction of patients at risk of severe nausea.

'Measuring up': A comparison of two response expectancy assessment formats completed by men treated with radiotherapy for prostate cancer.

OBJECTIVE: Response expectancies of cancer treatment toxicities are often, but not always, associated with subsequent experiences. A recent meta-analysis indicated that response expectancies, measured using different assessment formats, reveal different effect sizes, potentially explaining mixed outcomes. Utilizing a clinical sample, we compared 5-point assessments and visual analogue scales, as measures of response expectancies for the incidence and severity of subsequent toxicities. METHODS: Four weeks pre-radiotherapy, 45 men with prostate cancer rated their response expectancies of the same 18 toxicities on 5-point assessments and visual analogue scales, presented in random order. Descriptors anchored each end of visual analogue scales and every point of 5-point assessments was labelled, including an 'unsure' midpoint. Toxicities were subsequently assessed 2-weeks into radiotherapy on 100-point visual analogue scales. RESULTS: Across all toxicities, 17.5-62.8% of patients selected 'unsure' on 5-point assessments. No response expectancies were reported on 5-point assessments for 'blood in stools' or 'rectal urgency' yet 54.8%-64.3% of patients indicated response expectancies for these toxicities on visual analogue scales. Visual analogue scales and 5-point scales demonstrated small-to-moderate associations (r = 0.30-0.58) as measures of response expectancy incidence, but mostly large associations when visual analogue scales captured severity (r = 0.43-0.76). Response expectancies measured with visual analogue scales predicted more toxicities to a moderate degree or greater (68.8%) than 5-point assessments (37.5%). CONCLUSION: This novel investigation demonstrated an 'unsure' midpoint is often selected, potentially reducing the sensitivity of 5-point assessments. Based on their associations, and outcomes, these assessment formats should be considered independent in response expectancy research of cancer treatment toxicities.

The impact of valence framing on response expectancies of side effects and subsequent experiences: a randomised controlled trial.

Objective: Pre-treatment side effect expectancies often influence subsequent experiences; however, expectancy-based reduction strategies are lacking. We explored whether framing information about adverse responses (in positive or negative formats) altered expectancies and experiences of a cold pressor task. We further investigated associations between expectancies and experiences, to inform potential interventions. Design: Healthy volunteers (N = 134), randomised to receive positively- or negatively-framed pre-cold pressor task information, self-rated 12 expectancies for cold pressor experiences, emotional state and coping style. Main Outcome Measures: Self-reports of the same 12-experiences (recorded during and after the experiment) were assessed. Results: Framing had minimal impact on expectancies and experiences; however, discomfort threshold (p = .08, d = 0.22) showed a trend in the expected direction. Hierarchical regressions revealed expectancies uniquely, significantly predicted 6-23% of the variance for 11 subsequent experiences. Following a popular charity event (Ice Bucket Challenge), all participants showed higher 'discomfort thresholds' (p = .001, d = 0.59), and those in the negative frame reported more overall 'discomfort' (p = .01, d = 0.60) than participants in the positive condition. Conclusion: Expectancies uniquely influenced subsequent cold pressor experiences. Framing had minimal impact in this 'analogue' medical setting, only influencing 'discomfort threshold'. 'Discomfort threshold' and overall 'discomfort' were also impacted by a social media challenge, highlighting a potential area for intervention.

"Just As I Expected": A Longitudinal Cohort Study of the Impact of Response Expectancies on Side Effect Experiences During Radiotherapy for Prostate Cancer.

CONTEXT: Previous research has indicated that pretreatment response expectancies of side effects often predict subsequent toxicity severity. However, this has been largely based on female patients undergoing chemotherapy. OBJECTIVES: We tested whether this association also occurred in a novel cohort, men with prostate cancer undergoing radiotherapy. We investigated these associations throughout treatment (before and after side effects were medically predicted to occur), controlling known and novel variables. METHODS: Homogenous male patients scheduled for radiotherapy (N = 35, mean age 71 years) completed baseline (pretreatment) measures; response expectancies of 18 treatment-related side effects; questions about baseline health and hormonal treatment, emotional state, and coping style. Response expectancies of the side effects were again measured two weeks into treatment. The severity of the same 18 toxicities was assessed two and seven weeks into treatment. RESULTS: Hierarchical multiple linear regressions revealed baseline response expectancies significantly and independently predicted six of 18 toxicities two weeks into radiotherapy, contributing 12%-30% of explained variance (ß = 0.39-0.59). Response expectancies assessed two weeks into treatment significantly and uniquely predicted seven of 17 experienced toxicities at seven weeks, explaining 17%-50% of variance (ß = 0.49-0.91). Sexual toxicity response expectancies revealed the strongest associations with experience throughout treatment (ß = 0.46-0.91), with "inability to reach orgasm" showing the largest effect. CONCLUSION: In this older male sample, response expectancies of side effects predicted experiences throughout treatment, including the period before toxicities were medically expected. Response expectancies of sexual side effects were robust, independent predictors of subsequent toxicities across treatment, especially issues with orgasm, warranting focus in practice and future research.

Cancer Treatment Side Effects: A Meta-analysis of the Relationship Between Response Expectancies and Experience.

CONTEXT: Although previous research has, overall, suggested a moderate relationship between response expectancies (REs) and cancer treatment-related side effects, empirical results have been mixed. OBJECTIVES: We aimed to further explore these relationships, hypothesizing that REs would predict subsequent toxicities with the inclusion of more recent studies, across a broader range of side effects, while incorporating the impact of potential moderators including patients' experience with treatment and measurement methods. We further investigated the impact of REs across individual toxicities. METHODS: A systematic search and analysis were conducted across four databases (PsychInfo, PubMed, CINAHL, and Embase) and reference lists, from 1985 to February 2016. This provided 27 eligible studies with 4474 participants, through which the main analysis, moderator analyses, and individual side-effect analyses were explored. RESULTS: REs were moderately related to side effects overall (r = 0.26), and effect sizes were significantly influenced by sample diagnostic homogeneity, whereas differences between type and timing of measurement showed trends. Of the 16 toxicities examined, 15 demonstrated significant relationships between REs and side-effect experience, with hair loss (r = 0.48) the strongest. No clear difference emerged between objective and subjective side effects; however, significant differences across individual toxicities were revealed. CONCLUSION: Findings support a relationship between REs and a wide range of subsequent side effects, yet differences between individual RE-toxicity associations emerged. These findings provide direction for the measurement of side effects and REs and support REs as potential targets for intervention during the informed consent process.