The results of previous studies evaluated the accuracy of serum, and urinary measurements of cytokeratin-19 fragment (CYFRA 21-1) for the diagnosis of bladder cancer were inconsistent. We read with great interest the recent systematic review of diagnostic accuracy of CYFRA 21-1 for bladder cancer by Huang et al. The systematic analysis demonstrated that the pooled sensitivities and specificities for serum and urine CYFRA 21-1 were 0.42 (95 % confidence interval (CI), 0.33-0.51), 0.82 (95 % CI, 0.70-0.90), 0.94 (95 % CI, 0.90-0.96), and 0.80 (95 % CI, 0.73-0.86), respectively. Areas under the summary receiver-operating-characteristic curves for serum and urine CYFRA 21-1 were 0.88 (95 % CI, 0.85-0.91) and 0.87 (95%CI, 0.84-0.90), respectively. The authors considered that both serum and urine CYFRA 21-1 served as efficient indexes for bladder-cancer diagnosis. We congratulate and applaud their important work, but several important issues should be noted.
Keywords: Bladder cancer; Bladder carcinoma; CYFRA 21-1; Cytokeratin-19 fragment; Diagnosis.