Measuring What Matters: RECIST Response Does Not Predict HRQoL in Early-Phase Clinical Trials

Background/Objectives: Early-phase clinical trials (EPCTs) focus on safety and preliminary efficacy, often assessed by RECIST (Response Evaluation Criteria in Solid Tumours) tumour response. Health-related quality of life (HRQoL) is rarely evaluated in EPCTs and may not align with radiological outcomes. Methods: The PEARLER (Patient Experience in Early-Phase Cancer Clinical Trials) study evaluated the demographics, tumour response, HRQoL, and therapy type in two early-phase trial units in Australia between August 2023 and 2024. Patients completed the EORTC QLQ-C30 at baseline and follow-ups. The Global Health Status (GHS) score was selected as the primary HRQoL measure. Tumour response was assessed using RECIST 1.1. Spearman correlation and Kruskal-Wallis testing assessed the associations between RECIST, cross-sectional GHS change (ΔGHS; follow-up minus baseline), and therapy types. Multilevel models were used to evaluate longitudinal GHS values per RECIST category. Results: Of 122 patients recruited to the PEARLER study, 74 patients had paired RECIST and HRQoL data (complete response (CR) n = 0; partial response (PR) n = 15; stable disease (SD) n = 39; progressive disease (PD) n = 20). The median change in GHS was zero across RECIST groups, with broad individual variability. Notably, 18 of 54 patients (33.3%) with stable or responding disease experienced HRQoL decline. Meanwhile, 10 of 20 (50%) patients with PD experienced stable or improving HRQoL. The best RECIST response and ΔGHS showed a weak but statistically significant negative relationship (Spearman ρ = -0.28, p = 0.017), with the Kruskal-Wallis test demonstrating χ² = 6.20 (p = 0.045), indicating modest group differences driven by the deterioration in PD patients. The multilevel model demonstrated a lower GHS in patients with PD, with no statistically significant interaction of GHS change over time with the RECIST response (p = 0.226). Conclusions: HRQoL change is largely independent of radiologic tumour response and therapy type in EPCT participants. Patients experienced a HRQoL decline despite tumour response. Incorporating patient-reported outcomes alongside RECIST and safety outcomes is important to fully capture the impact of investigational therapies and guide patient-centred trial designs.