Self-perceived cognitive impairment in the first year after breast cancer and the identification of at-risk patients.

Cognitive functioning was assessed before start of any treatment (T0) and at 6 (T6) and 12 (T12) months after diagnosis. Cognitive functioning (CF) was measured on a scale of 0-100 with the EORTC QLQ-C30 questionnaire, and the EORTC pre-defined threshold for clinical importance. Multivariable logistic regression analyses was used to identify factors associated with new-onset clinically relevant cognitive impairment at T6 ((CF > 75 at T0 and CF < 75 at T6 and T12) or (CF > 75 at T0 and T6 and <75 at T12)).

One in five breast cancer patients reported clinically relevant cognitive problems before start of treatment. This percentage further increased within the first year, particularly among patients treated with chemo(immuno)therapy. One in five patients reported new-onset clinically relevant cognitive impairment. Ultimately, these patients may benefit from systematic monitoring and potential referral to interventions.

Pre-treatment, 21% of patients reported clinically relevant cognitive impairment. At T12, percentage was 32%; 20% of patients reported new-onset clinically relevant cognitive impairment at T6 and/or T12. New-onset clinically relevant cognitive impairment was associated with chemo(immuno)therapy and impairment in role and emotional functioning. Younger patients and patients receiving chemo(immuno)therapy were more likely to report new-onset clinically relevant cognitive impairment post treatment.

This study investigated self-reported clinically relevant cognitive impairment of breast cancer patients in routine clinical care and assessed factors associated with new-onset clinically relevant cognitive impairment.