Simple SummaryApproximately 30% of breast cancer survivors experience cancer-related cognitive impairment (CRCI) after cancer treatments. Given that CRCI adversely affects quality of life and increases the risk of stroke and dementia, there is an urgent need to identify who might be more vulnerable to CRCI, and how to improve outcomes. Several studies have suggested the possibility that individuals who are sensitive to uncertainty (i.e., intolerance of uncertainty (IU)) are more likely to experience cognitive problems. Consistent with these studies, our findings also showed that greater IU is associated with higher anxiety, and such higher anxiety lowers perceived cognitive function. While much is still to be learned about this association, this study suggests that identifying those with IU and anxiety could assist with identifying those at higher risk for CRCI and that IU and anxiety may be potential targets for future intervention studies.AbstractCancer-related cognitive impairment (CRCI) is one of the most prevalent symptoms that breast cancer survivors experience. While cancer treatments are established contributors to CRCI, inter-individual differences in CRCI are not well understood. Individual differences in sensitivity to uncertainty are potential contributors to CRCI; however, no prior studies have attempted to examine this link in the context of breast cancer. To address the gap, we used preliminary findings from an ongoing cross-sectional study. A total of 38 women with stage I–III breast cancer (1–4 years post-treatment) were included in this study. Intolerance of uncertainty (IU) was assessed using the Intolerance of Uncertainty Scale. Self-reported cognitive function was assessed with the Neuro-QoL questionnaire. Anxiety was assessed using the Patient-Reported Outcomes Measurement System Bank. From this study, we found that anxiety mediates the association between IU and cognitive function of survivors. In other words, among post-menopausal breast cancer survivors, those with higher IU showed higher anxiety and consequently had lower cognitive function. This finding suggests that assessing IU may help predict the risk of CRCI. This study expands the current knowledge that addresses the importance of IU as a factor associated with cognitive health.