Background <p>Cognitive impairment induced by chemotherapy and hormone therapy is a frequent side effect faced by an increasing number of breast-cancer survivors. The literature on the management of this cognitive impairment is still scarce, especially with regard to the application of non-pharmacological methods, such as Transcranial Direct Current Stimulation.</p> Case presentation <p>In this case report, we present a Brazilian Latin American Woman, 71&#xa0;years, breast-cancer survivor with cognitive complaints after adjuvant treatment and hormone therapy for the Luminal A subtype of the disease. We assessed general cognition, depression, verbal fluency, brain electrical activity in the right and left prefrontal regions of the brain (electrodes Fp1, Fp2, F3, F4, F7 and F8), level of physical activity and oxidative capacity before and after neuromodulation. The patient was submitted to a current of 2 milliamps on the Left Dorsolateral Prefrontal Cortex, three alternated days a week, totaling 12 sessions. Improvements in test scores were observed, with the exception of verbal fluency. Cortical activity, evaluated by electroencephalogram, was also modulated.</p> Conclusions <p>Transcranial Direct Current Stimulation appears to be a viable alternative to treat cognitive impairment related to antineoplastic treatment.</p> <p><i>Trial registration</i>: NCT04943003. Registered 29 June 2021, <a href="http://www.clinicaltrials.gov/ct2/show/NCT02772185">http://www.clinicaltrials.gov/ct2/show/NCT02772185</a>. Retrospectively registered.</p>