Transcranial Direct Current Stimulation for Cancer-related Cognitive Impairment in Breast Cancer Survivors

Efficacy and Mechanisms of Transcranial Direct Current Stimulation (tDCS) on Cancer-Related Cognitive Impairment(CRCI) in Breast Cancer Survivors: A Randomized Controlled Trial

This study aims to evaluate the efficacy of transcranial direct current stimulation (tDCS) in improving cancer-related cognitive impairment (CRCI) in breast cancer survivors. Participants will be randomly assigned to receive active or sham stimulation over the prefrontal cortex. Cognitive outcomes will be assessed using standardized neuropsychological tests and self-reported measures. Functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) will be used to explore neural correlates of intervention effects.

This study is designed to evaluate the therapeutic effects of transcranial direct current stimulation (tDCS) on cancer-related cognitive impairment (CRCI) in breast cancer survivors. CRCI is a common and persistent complication among patients treated with systemic cancer therapies and has a substantial impact on quality of life, even after completion of treatment. Participants will be female breast cancer survivors who have completed primary treatments and report cognitive complaints. Eligible individuals will be randomized in a 1:1 ratio to receive either active or sham tDCS. The stimulation will be applied over the left dorsolateral prefrontal cortex (DLPFC), a brain region involved in executive function, memory, and attention. Each participant will receive multiple sessions of tDCS across a defined intervention period. The primary outcome will be the change in perceived cognitive function, measured by the total score of the Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog) questionnaire. Secondary outcomes will include objective performance on neuropsychological tests (Trail Making Test, Auditory Verbal Learning Test, Digit Span Test), as well as patient-reported fatigue (Piper Fatigue Scale) and emotional symptoms (HAMD, HAMA). Neuroimaging (fMRI) and electrophysiological (EEG) data will also be collected in a subset of participants to explore neural correlates of treatment effects.

Inclusion Criteria:

1. Female breast cancer survivors aged 18-65 years.
2. Initially diagnosed with stage I-III non-metastatic breast cancer.
3. Between 6 months and 5 years after completion of initial curative surgery +/- radiation/chemotherapy.
4. allowed to be on endocrine therapy and/or anti-HER2 targeted therapy.
5. Self-reported cognitive complaints following cancer treatment.
6. Right-handedness (for standardized tDCS targeting)
7. Education level ≥ 6 years
8. Able and willing to undergo all study procedures (neuropsychological testing, MRI, EEG, etc.) and to provide written informed consent

Exclusion Criteria:

1. Contraindications to MRI or EEG (e.g., pacemaker, metallic implants, claustrophobia).
2. Active neurological/psychiatric disorders (e.g., major depressive disorder, bipolar disorder, schizophrenia, Parkinson's disease, post-stroke sequelae)
3. Concurrent use of cognition-enhancing medications (e.g., donepezil, memantine)
4. Severe somatic diseases (cardiac/hepatic/renal insufficiency)
5. Pregnant or breastfeeding
6. Concurrent participation in another interventional clinical trial