Reducing Breast Cancer-related Fatigue and Improving Cognition With Non-Invasive Brain Stimulation

Inclusion Criteria: * Women, 18 years of age or older * Stage I-III breast cancer * Treatment Status: At least 6 months and no more than 5 years after the conclusion of active breast cancer therapy, including surgery, radiation therapy and (neo)adjuvant chemotherapy, if administered. NOTE: Adjuvant HER2-targeted therapy and endocrine therapy may still be ongoing at the time of study enrollment. * Fatigue: Moderate fatigue on most days within the past week (i.e., at least 4 out of the last 7 days), rated as ≥ 4 on a 0 (no fatigue) to 10 (worst fatigue) scale. * Able and willing to complete study tasks as evidenced by at least the following: fluent English speaker; hearing and language comprehension; and, sufficient literacy to complete study forms and questionnaires. * Patient understands the study regimen, its requirements, risks, and discomforts, and is able and willing to sign an informed consent form. Exclusion Criteria: * Evidence of recurrent breast cancer at the time of enrollment. * Depression or anxiety as defined either by ongoing pharmacological treatment for depression or anxiety or a HADS score on initial screening. * Dementia as assessed by a MMSE score on initial screening. * Known pregnancy or nursing. * Any of the following: diagnosis of schizophrenia or bipolar disorder made by a physician, seizure disorder, pacemaker, hearing aids, any metal implanted in the head, or the presence of other known current untreated causes of fatigue such as anemia or untreated hypothyroidism. * Use of stimulant medications, sleep medications, nicotine patch, and other drugs thought to interfere with tDCS efficacy for seven days prior to and during study participation. * Use of narcotic pain medication, benzodiazepines, or illicit drugs for seven days prior to and during study participation. * Consumption of \>14 alcoholic drinks per week or positive screening on the CAGE. * Skin conditions involving open sores on the scalp that would prevent proper application of the electrodes. * Hairstyles that obstruct placement of the electrodes including cornrows, dreadlocks, braids or other hair accessories that cannot be removed. * Other medical or other condition(s) that in the opinion of the investigators might compromise the objectives of the study.