Cancer survivors are exposed to several risk factors for cognitive dysfunction, such as general anesthesia, surgical trauma, and adjuvant therapies. In our recent study we showed that thalamic volume reduction and attentional dysfunction occurred shortly after surgery. Here, we examined the 6-month prognosis of the 20 patients with breast cancer who underwent surgery. Seven patients did not receive any adjuvant therapy after the surgery and 13 patients received a hormonal therapy after the surgery. We assessed their attentional functions, and thalamic volumes shortly after and 6 months after surgery. We found a significant group x time interaction in the attentional functions (p = 0.033) and the right thalamus (p < 0.05, small volume correction), suggesting the thalamic volume reduction and attentional dysfunction recovered in patients without adjuvant therapy. Our findings provide a better understanding of the potential role of hormonal therapy in relation to the cognitive dysfunction of cancer survivors.