https://www.selleckchem.com/products/tariquidar.html Older adults with advanced cancer face uncertainty related to their disease and treatment. To evaluate the associations of uncertainty with psychological health and quality of life (QoL) in older adults with advanced cancer. Secondary cross-sectional analysis of baseline data from a national clustered geriatric assessment trial. Patients 70years and older with advanced cancer considering a new line of chemotherapy were recruited. We measured uncertainty using the modified nine-item Mishel Uncertainty in Illness Scale. Dependent variables included anxiety (Generalized Anxiety Disorder-7), depression (Generalized Depression Scale-15), distress (distress thermometer), QoL (Functional Assessment of Cancer Therapy-General), and emotional well-being (Functional Assessment of Cancer Therapy-General subscale). We used multivariate linear regression analyses to evaluate the association of uncertainty with each dependent variable. We conducted a partial least squares analysis with a variable importance in projection (VIP) plot to assess the contribution of individual variables to the model. Variables with a VIP <0.8 were considered less influential. We included 527 patients (median age 76years; range 70-96). In multivariate analyses, higher levels of uncertainty were significantly associated with greater anxiety (β=0.11; SE=0.04), depression (β=0.09; SE=0.02), distress (β=0.12; SE=0.02), as well as lower QoL (β=-1.08; SE=0.11) and emotional well-being (β=-0.29; SE=0.03); the effect sizes were considered small. Uncertainty items related to disease and treatment were most strongly associated with psychological health and QoL scores (all VIP >0.8). Uncertainty among older patients with advanced cancer is associated with worse psychological health and QoL. Tailored uncertainty management strategies are warranted. Uncertainty among older patients with advanced cancer is associated with worse psychological health and QoL. Tailore