Biomedical subjects

Stacy Childs

Publications and source records attributed to Stacy Childs.

4 recordsLinked to original sources

PubMed2003

Volume indexes of total, free, and complexed prostate-specific antigen enhance prediction of extraprostatic disease extension in men with nonpalpable prostate cancer.

OBJECTIVES: To analyze the ability of volume-adjusted total, complexed, and free prostate-specific antigen (PSA) to predict organ-confined cancer at radical prostatectomy in patients with nonpalpable disease. METHODS: Collected sera were assayed for total PSA (tPSA), complexed PSA (cPSA), and free PSA (fPSA) in 78 men who underwent radical prostatectomy with nonpalpable prostate cancer. The pathologic results (organ-confined versus extraprostatic extension [EPE]), tPSA, cPSA, fPSA/tPSA ratio, cPSA/tPSA ratio, fPSA/cPSA ratio, tPSA density (tPSAD), cPSA density (cPSAD), and fPSA density (fPSAD) were compared by the Mann-Whitney U test and receiver operating characteristic curves. RESULTS: Fifteen men (19.2%) had pathologic EPE. After stratifying the patients on the basis of the Beckman tPSA, the cPSAD, tPSAD, and fPSAD were significant predictors of EPE when comparing their respective medians in individuals with tPSA greater than 4.0 ng/mL. Statistically significant differences were noted between patients with and without EPE for tPSAD (P = 0.0015), cPSAD (P = 0.0018), and fPSAD (P = 0.0022), but not for the fPSA/tPSA, cPSA/tPSA, and fPSA/cPSA ratios. The area under the receiver operating characteristic curve was similar for tPSA (0.539) and cPSA (0.542), as it was for tPSAD (0.708), cPSAD (0.700), and fPSAD (0.731). The specificity and diagnostic accuracy of tPSAD, cPSAD, and fPSAD were significantly greater than those of tPSA and cPSA (specificity P <0.001; diagnostic accuracy P <0.05). CONCLUSIONS: In men with nonpalpable prostate cancer, the density parameters of tPSA, cPSA, and fPSA performed equivalently and appeared to enhance the predictability of EPE.

Adenocarcinoma↗

PubMed2002

Complexed prostate-specific antigen for early detection of prostate cancer in men with serum prostate-specific antigen levels of 2 to 4 nanograms per milliliter.

Complexed PSA (cPSA) has been shown to improve specificity in the detection of prostate cancer over that of total PSA (tPSA) testing in men with tPSA values greater than the cutoff value of 4.0 ng/mL. However, recent studies have reported a 25% incidence of prostate cancer in men with tPSA values in the 2.5- to 4.0-ng/mL range. We performed a multicenter study of cPSA in a population of men who underwent prostate biopsies because of elevated PSA levels or abnormal digital rectal examination (DRE). As part of this study, we sought to assess the clinical value of cPSA in comparison to tPSA, the free/tPSA ratio (f/tPSA) and the complexed/tPSA ratio (c/tPSA) in early detection of prostate cancer in men with tPSA values in the range of 2 to 4 ng/mL. The study was performed at 7 centers. Sera were drawn from men who underwent biopsy procedures consisting of >10 prostate tissue cores. Receiver operating characteristic (ROC) analysis was performed from the results of patients with tPSA values in the range of 2 to 4 ng/mL, including men with suspicious as well as unremarkable findings on DRE. Sera were collected and tested with the Bayer tPSA and cPSA assay and the Beckman free PSA and tPSA assays. ROC analysis was performed for all samples in the 2- to 4-ng/mL PSA range. At biopsy, 158 men had no evidence of malignancy and 57 (26.5%) were diagnosed with prostate cancer. ROC analysis indicated that the area under the curve (AUC) for cPSA was 0.64, which was statistically significantly greater than that achieved for tPSA (AUC, 0.57; P <0.0001). The AUC for f/tPSA and c/tPSA were 0.60 and 0.63, respectively, which was not statistically significantly different from that of tPSA or cPSA (P >or=0.252). A cutpoint of 2.5 ng/mL for tPSA and 2.1 ng/mL for cPSA provided a specificity of 20.3% and 34.2%, respectively, and sensitivity levels of 86%. Using cutpoints of 25% for f/tPSA and 74% for c/tPSA provided a specificity of 11.0% and 21.5%, respectively, and sensitivity levels of 97%. In all, >92% of the cancers treated with radical prostatectomy were organ confined, and the histologic grading of the tumors ranged from moderately to poorly differentiated with Gleason scores from 5 to 9. These data confirm that there is a high incidence of clinically significant prostate cancer in men with tPSA levels <4.0 ng/mL. Measurement of cPSA proved useful in stratifying men with tPSA values in the 2- to 4-ng/mL range into high- and low-risk groups for prostate cancer. The use of cPSA as a single test was found to enhance detection of prostate cancer over that of testing with tPSA and PSA ratios in men with tPSA values in the range of 2 to 4 ng/mL.

Adult↗

PubMed2002

Can volume measurement of the prostate enhance the performance of complexed prostate-specific antigen?

We assessed whether volume-based complexed prostate-specific antigen (cPSA) indices could enhance prostate cancer detection in men with serum total PSA (tPSA) between 2.5 and 10.0 ng/mL. Between December 1998 and April 2000, cPSA assay was measured in 480 men who underwent transrectal ultrasound-guided prostate biopsies at 7 institutions. We compared the usefulness of cPSA and its indices with the ratio of free PSA (fPSA) to tPSA (percent fPSA) for early detection of prostate cancer. Overall, 168 men (35%) had cancer. In the 341 men with tPSA between 4.01 and 10.0 ng/mL at approximately 90% sensitivity and areas under the receiver operating characteristics curve, the performances of volume-based parameters were significantly better (P <0.05) than those of tPSA and cPSA. In the 139 men with tPSA between 2.5 and 4.0 ng/mL, at 90% sensitivity, the specificity of the ratio of cPSA to tPSA (percent cPSA) was best, followed by cPSA density (cPSAD). In the 101 men with the history of a previous prostate biopsy, at approximately 90% sensitivity, the specificity of cPSAD was significantly better than those of tPSA and percent fPSA (P <0.05). In the 371 men with a total prostate volume of >or=30 cm(3) at approximately 90% sensitivity, the specificity of the cPSAD was significantly better than that of tPSA, percent fPSA, and cPSA (P <0.05). In the 109 men with a total prostate volume of <30 cm(3), at 90% sensitivity the specificity of cPSA and cPSAD was better than that of percent fPSA. In conclusion, volume-based cPSA can modestly enhance the performance of cPSA.

Humans↗

PubMed2002

Complexed prostate-specific antigen as a staging tool: results based on a multicenter prospective evaluation of complexed prostate-specific antigen in cancer diagnosis.

Within a 7-site prospective evaluation of the Bayer complexed prostate-specific antigen PSA (cPSA) assay, we analyzed the ability of cPSA to predict extracapsular extension (ECE) before radical prostatectomy. Included in this analysis were 152 men diagnosed with cancer, who subsequently underwent radical prostatectomy. Sera were tested with the Bayer total PSA (tPSA) and cPSA assays, and the Beckman free PSA (fPSA) and tPSA assays. Treating surgical pathology result as a binary variable (organ confined vs ECE), mean tPSA, cPSA, fPSA/tPSA (f/tPSA) ratios, tPSA density (tPSAD), and cPSA density (cPSAD) were compared by receiver operating characteristic (ROC) curves and univariate analysis. In all, 28 men (18.4%) had pathologically identified ECE. Between those with and without ECE, significant differences were observed for tPSA (P = 0.0127), cPSA (P = 0.0120), tPSAD (P = 0.0001), and cPSAD (P = 0.0002), but not f/tPSA (P = 0.3774) or c/tPSA (P = 0.2882). All tested parameters except f/tPSA (P = 0.376) and c/tPSA (P = 0.288) predicted ECE (P <0.05) by logistic regression. The ROC area under the curve (AUC) was identical for tPSA and cPSA (0.621) and for tPSAD (0.692) and cPSAD (0.691). Kendall-tau correlation coefficients also demonstrated the strongest correlation with ECE for cPSAD and tPSAD. Either alone or as a tPSAD calculation, cPSA carries equivalent staging ability to tPSA. The use of f/tPSA appears to be less effective in staging than either cPSA or tPSA, whereas the use of either cPSAD or tPSAD provides maximal staging accuracy. Therefore, cPSA could be applied as an accurate predictor of ECE independently or in a nomogram along with other predictive variables.

Aged↗