Racial disparity in preoperative C-reactive protein level for predicting prognosis of patients with non-metastatic clear cell renal cell carcinoma: INMARC study

Background: C-reactive protein (CRP) is a prognostic biomarker for clear cell renal cell carcinoma (ccRCC). However, there may be potential racial heterogeneity in distribution and prognostic impact of CRP level. We investigated potential racial differences in distribution and prognostic impact of preoperative CRP among Asian (AS), African American (AA), and Caucasian (CAUC) patients with non-metastatic ccRCC (nmccRCC).

Methods: We retrospectively analyzed 1991 nmccRCC cases (AS/AA/CAUC: n = 968/223/800) undergoing nephrectomy from the international multi-institutional database. We investigated CRP distributions and optimal cut-off values for predicting recurrence-free survival (RFS) and overall survival (OS) using Cox regressions for each racial group. Subgroup analyses considered comorbidities, pathological T stage, and Fuhrman grade.

Results: Preoperative CRP distributions differed significantly among the races, with median values of 0.90 mg/L (interquartile range, 0.40-2.33) for AS, 5.00 mg/L (1.98-12.20) for AA, and 3.55 mg/L (1.41-8.48) for CAUC (p < 0.01). Optimal cut-off values for RFS were 1.2 mg/L in AS, 2.8 mg/L in AA, and 1.7 mg/L in CAUC, showing C-indices of 0.77, 0.71, and 0.77, respectively. For OS, they were 1.6 mg/L in AS, 8.3 mg/L in AA, and 9.3 mg/L in CAUC, yielding C-indices of 0.77, 0.70, and 0.74, respectively. Subgroup analyses revealed varying reference ranges of CRP levels among races (1.1-2.2/2.7-5.0/1.5-3.4 mg/L for RFS, and AS/AA/CAUC: 0.9-3.0/8.0-12.7/8.0-10.4 mg/L for OS, respectively).

Conclusion: The preoperative CRP distributions and their optimal cut-off values for predicting patient prognosis differed significantly among the races. Using race-specific cut-off values, CRP demonstrated consistently high-prognostic accuracies, which may improve tailored patient management in nmccRCC.