AimsHealth‐related quality of life (HRQoL) is highly relevant in cancer and often assessed with the EORTC QLQ‐C30. Cardiovascular HRQoL in cancer can be measured with the ESC HeartQoL questionnaire. We compared these instruments and examined their prognostic value.MethodsSummary scores for EORTC QLQ‐C30 (0‐100 points) and HeartQoL (0‐3 points) questionnaires were prospectively assessed in 290 patients with mostly advanced cancer (stage 3/4: 81%, 1‐year mortality: 36%) and 50 healthy controls (similar age and sex). Additionally, physical function and activity assessments were performed.ResultsBoth questionnaires demonstrated reduced HRQoL in patients with cancer vs controls (EORTC QLQ‐C30: 67±20 vs 91±11, p<0.001; ESC HeartQoL: 1.8±0.8 vs 2.7±0.4, p<0.001). The instruments were strongly correlated with each other (summary scores (r=0.76), physical (r=0.81), and emotional subscales (r=0.75, all p<0.001)) and independently associated with all‐cause mortality (best cut‐offs: EORTC QLQ‐C30 <82.69: hazard ratio (HR) 2.33, p=0.004, HeartQoL <1.50: HR 1.85, p=0.004 – adjusted for sex, age, left ventricular ejection fraction, NT‐proBNP, hsTroponinT, cancer stage/type), with no differences in the strength of the association by sex (p‐interaction>0.9). Combining both questionnaires identified three risk groups with highest mortality in patients below both cut‐offs (vs. patients above both cut‐offs: HR 3.60, p<0.001). Patients with results below both cut‐offs, showed higher NT‐proBNP and reduced physical function and activity.ConclusionsEORTC QLQ‐C30 and ESC HeartQoL – assessing cancer and cardiovascular HRQoL – are both associated with increased mortality in cancer patients, with even greater stratification by combing both. Reduced HRQoL scores were associated with elevated cardiovascular biomarkers and decreased functional status.This article is protected by copyright. All rights reserved.