Validation of the CAIX score as a prognostic biomarker for lymphatic spread and cancer-specific survival.

Abstract

454 Background: We recently developed a novel CAIX density scoring system that was found to be a significant prognostic biomarker in a cohort of patients with high-risk clear cell renal cell carcinoma (ccRCC). We sought to validate the association of CAIX score with lymphatic spread and survival in a cohort of patients with ccRCC. Methods: We reviewed the clinical and pathologic records of 418 patients who underwent radical nephrectomy at UCLA between 1985 and 1999. Clinical features included age, gender, race/ethnicity, and ECOG performance status. Pathologic features included TNM stage, nuclear grade, UCLA Integrated Staging System (UISS), and CAIX staining. CAIX score was stratified into low (0–99), intermediate (100–199), and high (200–300). We examined the association between the CAIX score, disease severity, and survival using logistic and Cox regression analyses, respectively. Results: Mean CAIX score was 237.4 (SD 98.3). Approximately 26% of patients with low CAIX scores had lymphatic involvement, compared with 28% of those with intermediate scores, and 8% with high scores, p<0.01. On multivariate analysis, patients with high CAIX scores had a significantly lower risk of lymphatic involvement (OR 0.19, p<0.01). When compared with those with low CAIX scores, patients with high CAIX scores were significantly less likely to recur (HR 0.53, p=0.02) or die (HR 0.41, p<0.01). Patients with intermediate scores were no less likely to recur HR 0.93, p=0.85) or die of their disease (HR 0.69, p=0.34). Lastly, patients with high-risk non-metastatic ccRCC were less likely to recur (HR 0.04, p<0.01). Conclusions: The CAIX score can help identify the majority of patients presenting with lymphatic spread and serves as a statistically significant prognostic biomarker for recurrence-free and disease-free survival after nephrectomy. We recommend that utility CAIX score be quantified for all patients with high-risk disease.