Relationships between patients' pre-treatment expectations of toxicities and post chemotherapy experiences.

A lack of adequate pharmacological explanations for side effect variation following chemotherapy suggests psychological factors may contribute to toxicity experience. This research aimed to determine if patients' expectations were associated with perceived toxicities for a wider range of chemotherapy toxicities than previously researched, including subjective and objective side effects. Eighty-seven chemotherapy-naive patients rated their expectations of 20 common side-effects before treatment, and then rated their experiences following their first chemotherapy dose. Hierarchical multiple regression analyses revealed that expectations of the inability to concentrate, hair loss, and diarrhoea prior to treatment had the strongest associations with the experience of symptoms. Expectations of encountering problems with sleep and sex, changes in taste or appetite, weakness, and nervousness, all showed moderate associations, and expectations of mood changes, feelings of tiredness, and nausea all showed weak associations with experience. These outcomes suggest that subjective side effects may be more prone to influence by expectation given their ambiguous nature. However, further research needs to be conducted into the effect expectations have on the treatment process, including the impact of other psychological factors. The current overriding emphasis placed on personal autonomy and fully informed consent may set up negative expectations which translate into adverse experiences to the detriment of the patient.