Tumor burden is not related to quality of life in patients with metastatic colorectal cancer

Abstract

4017 Background: The significance of tumor burden (TB), as both a prognostic and an outcome measure in colorectal cancer patients (pts) has recently come under scrutiny. Tumor response endpoints have been poor predictors of overall survival (OS). There has been mounting evidence that QOL has prognostic significance (Sloan, JCO, 1998). The purpose of this study was to describe the relationship between TB and QOL in pts with metastatic colorectal cancer (MCRC). Methods: 989 pts with MCRC participating in Intergroup study N9741 provided data at baseline (bl) and every 12 weeks (wk) on overall QOL and fatigue (single-item numerical analogues), and total symptom distress (McCorkle Symptom Distress Scale [SDS]). TB was represented by actual tumor measurements (TM) and as an ordinal tumor response. A 10-point change on a 0–100 point scale was defined a priori as clinically meaningful in QOL-related variables. The sample size provided over 90% power to detect all but the smallest effect size (<0.1 Standard Deviation) for all statistical procedures involved, so p-values alone are of limited relevance. Results: We observed weak correlations among TM at bl and QOL (-0.07), fatigue (-0.18), and symptom distress (-0.14), indicating lack of any strong relationship. Changes from bl scores to 12 wk in TM were not associated with changes in QOL, fatigue, or symptom distress (correlations of -0.003, 0.06, and 0.05 respectively). Correlation between QOL and bl TM remained consistently low across subsets based on patient performance status and age. Concordance between patients reporting a tumor response and a clinically meaningful improvement at 12 wk in QOL, fatigue, or symptom distress was only 12.9%, 9.6%, and 11.9% respectively. Similarly, only 67.7%, 57%, and 59.7% of the patients reporting a clinically significant improvement in QOL, fatigue, and symptom distress had a tumor response. Conclusions: There was little evident relationship between the QOL-related variables and TB in these patients, suggesting that changes in TB have little impact on how the patient feels. These data raise questions about the value of tumor response as an endpoint with immediate clinical relevance for patients with advanced colorectal cancer (ACRC). No significant financial relationships to disclose.