Background: Mindfulness has been applied to improve after cancer care by enhancing psychological well-being; however, little is known about its impact on cognitive impairment experienced by cancer patients after chemotherapy. Mindfulness may be relevant in tackling cognitive impairment by decreasing emotional distress and fatigue, by decreasing inflammation, and by strengthening brain functional connectivity. The aim of the present study protocol is to evaluate the efficacy and mechanisms of a mindfulness-based intervention to reduce cognitive impairment in breast-cancer patients after chemotherapy.

Methods: The present study is a three-group randomized controlled trial with assessments at baseline, one-three weeks after the intervention and at three months follow-up. One hundred twenty breast cancer patients who ended treatment minimum 6 months and maximum 5 years before and who have cognitive complaints will be enrolled. They will be randomized into one of the following three study arms: (1) a mindfulness-based intervention group (n=40), (2) an active control condition based on physical training (n=40), or (3) a waitlist control group (n=40). Both the mindfulness-based intervention and the active control condition exist of four group sessions (3 hours for the mindfulness condition and 2 hours for the physical training) spread over 8 weeks. The primary outcomes will be cognitive complaints as measured by the cognitive failure questionnaire and changes in brain functional connectivity in the attention network. Secondary outcomes will be (1) levels of emotional distress, fatigue, mindfulness; (2) neurocognitive tests; (3) structural and functional brain changes using MR imaging, and (4) inflammation.

Discussion: The study will examine the impact of a mindfulness-based intervention on cognitive impairment in breast-cancer patients. If the findings of this study confirm the effectiveness of a mindfulness-based program to reduce cognitive impairment, it will be possible to improve quality of life for ex-cancer patients. We will inform health care providers about the potential use of a mindfulness-based intervention as a non-pharmaceutical, low-threshold mental health intervention to improve cognitive impairment after cancer.

Inclusion Criteria:

• diagnosis of breast cancer at an early stage with or without solitary metastases (except solitary brain metastases)
• completed treatment (surgery and chemotherapy) minimum 6 months and maximum 5 years before
• significant cognitive complaints as measured by the Cognitive Failure questionnaire (CFQ total score > mean study Ponds + 1 SD or on 2 or more of the CFQ extra questions (T/E) > mean study Ponds + 1 SD; (Ponds, Van Boxtel, & Jolles, 2006))
• have sufficient understanding of Dutch

Exclusion Criteria:

• a history of mental retardation, psychiatric and or neurological disorder
• previous participation in a mindfulness training