ABSTRACT
Objective To determine the value of complexed prostate-specific antigen (cPSA) in predicting metastasis in patients with prostate cancer.Methods From January 2012 to April 2014,the clinical data of 74 patients with newly diagnosed prostate cancer in our hospital was retrospective reviewed.The prostate cancer was diagnosed by transrectal ultrasound guided biopsy and postoperative pathologic diagnosis.The patients were divided to 2 groups according to metastases status.There were 38 patients in the group of metastasis and 36 patients in the group of without metastasis.In metastasis group,the bone metastasis was found in 36 cases.There is only one case with lung metastasis and one case with lymph node metastasis.In the group without metastasis,the T stages classification were T1-T2 in 17 cases and T3-T4 in 19 cases.While,10 cases with T1-T2 stage and 28 cases with T3-T4 stage were confirmed in the group with metastasis.There was no statistical significance of T stages and mean age in two groups (P＞0.05).The level of cPSA in the serum was detected by chemiluminescent immunoassay,the level of tPSA,fPSA were detected by electro-chemiluminescent immunoassay,fPSA/tPSA,cPSA/tPSA were evaluated and the corresponding specificity were calculated.The correlation of age with tPSA,cPSA were analysed.The differences in PSA,fPSA/tPSA,cPSA/tPSA were compared between metastasis and non-metastasis group.ROC curve analysis was used to determine the diagnostic value of cPSA and tPSA,In the meantime,area of ROC curves were compared by Z test.Results The age was not related to the value of tPSA (r=-0.09,P=0.12) and cPSA(r=-0.38,P=0.14).The median levels of tPSA,fPSA,and cPSA are 29.88μg/L,2.18 μg/L and 18.86 μg/L in the group without metastasis,respectively.The median levels of tPSA,fPSA,and cPSA were 410.05 μg/L,51.50 μ.g/L and 290.40 μg/L in the group with metastasis,respectively.Significant differences of those results could be found in two groups (P＜0.05).fPSA/tPSA was 0.07 and cPSA/tPSA was 0.79 in the group without metastasis.fPSA/tPSA was 0.08 and cPSA/tPSA was 0.80 in the group of metastasis.fPSA/tPSA (P=0.77),cPSA/tPSA (P=0.64) in patients with metastasis were not greater than in those without metastasis (P＞0.05).The area under the curve of tPSA and cPSA were 0.83 (95％ CI 0.73-0.93) and 0.82 (95％CI 0.73-0.92) respectively.Analysis of ROC curves showed that the AUC for cPSA is not significant different from tPSA (Z=1.64,P=0.10).The specificity of cPSA was 22.2％ which is higher than that of tPSA (19.4％) at a sensitivity of 92.1％ in predicting metastasis comparing with the patients without metastasis.The sensitivity could reach to 90.0％ when the cut off value of tPSA was 9μg/L or the cut off value of cPSA was 7 μg/L.Conclusions In our study,a preliminary validation that cPSA is useful for predicting the metastasis in patients with prostate cancer was made.