Cancer - Prostate(구연) (E-137)

Assessment of agreement between two difference prostate specific antigen assay modalities
성균관의대 삼성서울병원, 비뇨의학과 교실
정재훈, 송완, 강민용, 성현환, 전황균, 정병창, 서성일, 이현무, 전성수
Purpose: There is controversy over the usefulness of prostate specific antigen (PSA) as a prostate cancer (PCa) biomarker. This controversy can arise when there are differences in the results of PSA assay modalities. To evaluate of proper validation between the two PSA assay modalities, the agreement between the results of the two modalities was analyzed.
Methods: PSA examinations were conducted using two PSA assay modalities in 4,810 patients. The intra-class correlation coefficient (ICC) and weighted kappa analysis was used to evaluate the agreement between the two assay modalities. A linear regression was performed to evaluate the association between the two assay modalities.
Results: According ICC values (ICC: 0.9989, p < 0.001)(Table 1) and Weighted kappa analysis values (kappa: 0.951, ASE: 0.001, p < 0.0001)(Table 2), the agreement between the assay modalities was rated as excellent. However, the strength of agreement was poor in the following PSA sub-groups: 0.05–0.1 ng/mL (ICC: 0.2810, p = 0.0860); 0.15–0.2 ng/mL (ICC: 0.2881, p = 0.0036); 1.5–2.0 ng/mL (ICC: 0.3598, p = 0.0860); and 2.0–2.5 ng/mL (ICC: 0.3029, p = 0.0868) (Table 1). In linear regression analysis, when modality B PSA yielded a value of 0.2 ng/mL, the expected value for modality A was 0.258 ng/mL (95% CI: 0.255–0.260), and 4 ng/mL with an expected value at 3.192 ng/mL (95% CI: 3.150–3.235).
Conclusion: The difference in the PSA values between two PSA assay modalities is confirmed, and this difference would be clinically meaningful.
keywords : Prostate-Specific Antigen, Prostate cancer, Diagnosis