Biomedical subjects

J C Petteway

Publications and source records attributed to J C Petteway.

5 recordsLinked to original sources

PubMed1997

Comparison of three commercial PSA assays: results of restandardization of the Ciba Corning method.

BACKGROUND: Consistency in prostate-specific antigen (PSA) quantitation by different PSA test manufacturers would minimize potential clinical confusion. The Ciba Corning ACS PSA2 calibration has been adjusted for alignment with a proposed international standard and clinical concordance with the Hybritech Tandem R assay. Herein we evaluate the clinical effectiveness of this recalibrated PSA test by comparing it with the IMx (Abbott Laboratories) and Tandem R (Hybritech) assays. METHODS: Archival serum was used that had been stored at -70 degrees C from men who underwent ultrasound-guided prostate needle biopsy. Assays were run according to each manufacturer's specifications in singlicate on a single thaw. RESULTS: The study included sera of 191 patients; 44 of the patients had carcinoma. There were 151 men with PSA (Tandem R) in the range of 0-10.0 ng/ml, 28 of whom had cancer. The correlation coefficients for Tandem R versus ACS, Tandem R versus IMx, and ACS versus IMx were 0.958, 0.955, 0.979 for benign patients and 0.960, 0.954, and 0.985 for those with cancer, respectively. The corresponding slopes were 1.029, 0.855, and 0.824 for men without and 1.044, 0.830, and 0.790, respectively, for those with malignancy. CONCLUSIONS: These data demonstrate substantial equivalence of the restandardized ACS assay and of the Hybritech method. Significant bias exists between these methods and the IMx assay with lower results being identified with the latter. These findings have significant implication, particularly in screening when results of an IMx assay are compared to other assays.

Evaluation Studies as Topic↗

PubMed1996

Age-specific prostate-specific antigen: a reassessment.

BACKGROUND: Our objective was to compare expected survival benefits when screening for prostate cancer with PSA, using an age-specific bound relative to a cutoff of 4.0 ng/ml. METHODS: We used a decision analysis modeling the cancer yield in a cohort screened by both screening tests, and the survival of cancer cases given screen detection and in the absence of screening. Expected cancer yields and positive predictive values were from an ultrasound-guided biopsy series. Stage distributions of screen-detected cases were obtained from the literature. For localized causes, survival given screen detection was assumed to be equal to normal life expectancy for the population. For these cases, survival in the absence of screening was modeled as time from clinical diagnosis to death added to time remaining after time of screen and before clinical diagnosis was made (lead time). For nonlocalized cases at screen detection, survival given screen detection was assumed to be equal to survival in the absence of screening. The average difference between expected survival with and without screening as calculated for age-specific PSA and for PSA > 4.0 ng/ml and compared. RESULTS: Average years of life saved per subject screened using PSA > 4.0 ng/ml were comparable to those using the age-specific bound. Average years of life saved per cancer case, however, appeared to be potentially greater for PSA > 4.0 ng/ml than for age-specific. PSA. PSA > 4.0 ng/ml detected markedly more prostate cancer cases than age-specific PSA. CONCLUSIONS: Using a bound of 4.0 ng/ml for all ages appears to be more efficient in identifying men with cancer in a screening cohort, which translates into a greater expected survival benefit per cancer case.

Aged↗

PubMed1996

Multicenter comparison of the diagnostic performance of free prostate-specific antigen.

OBJECTIVES: This study examined the multicenter clinical performance of noncomplexed (free) prostate-specific antigen (PSA) in men presenting with total PSA values between 2.5 to 20 ng/mL. METHODS: Prebiopsy serum samples were obtained from 1,081 consecutively accrued, histologically diagnosed men between the ages of 40 and 75 years with total PSA values falling between 2.5 and 20 ng/mL. Total PSA was determined by either the Tosoh AIA-1200 or Hybritech method. Free PSA values were determined using the Dianon PSA II immunoradiometric method. Free PSA was expressed as a percentage of total PSA. Immunochemistry was performed at each accrual site. RESULTS: Among men diagnosed with prostate cancer (CaP), only 4% (21/520) had proportions of free to total PSA values > 25%. Conversely, among men with benign prostatic disease, only 2% (13/561) had proportions of free to total PSA values < 7%. These results confirm those of previous research. Differences among sites were found in age and prostate volume. CONCLUSIONS: These data confirm that free PSA values < 7% are highly suspicious for CaP whereas free PSA values > 25% suggest absence of malignancy. The data also suggest that age and/or prostate volume influences the serum level of free PSA but does not affect the diagnostic cutoff points of 7% and 25%. Future analysis is needed to confirm that younger men with small prostates are at higher risk for CaP.

Adult↗

PubMed1995

Serum basic fibroblast growth factor in men with and without prostate carcinoma.

BACKGROUND: Angiogenesis is essential for the growth of neoplasms. Increased vascularity has been associated with human prostatic carcinoma stage and has been shown to offer prognostic information. Basic fibroblast growth factor (bFGF) is a potent angiogenic inducer expressed in malignant prostate tissue. In this investigation, serum bFGF levels were measured in men with and without prostate cancer. METHODS: Serum bFGF was measured using a commercial enzyme-linked immunosorbent assay in archival serum from men with various clinical stages of prostate carcinoma. Sera from men with negative systematic sector biopsies and serum prostate specific antigen (PSA) less than 2.0 ng/ml served as controls. Prostate volume was measured with transrectal ultrasound. RESULTS: Serum bFGF level was significantly higher in men with prostate carcinoma compared with those without (P < 0.0007). Among 44 men (11 with carcinoma) with a serum PSA less than 4.0 ng/ml, only bFGF level was associated with carcinoma (P = 0.008). Using a cutoff of 1.0 pg/ml, bFGF afforded a sensitivity of 83% and specificity of 44% in this group. There was no association between bFGF levels and clinical stage, Gleason score, or prostate volume. CONCLUSIONS: These data demonstrate that serum levels of bFGF are elevated in most men with prostatic carcinoma. Although association with stage was not observed, the finding of significant elevation in most men with carcinoma who have "normal" serum PSA levels may indicate diagnostic utility for this analyte.

Aged↗

PubMed1995

Assay variability in serum prostate-specific antigen determination.

Consistency and reproducibility of serum prostate-specific antigen (PSA) measurement are essential in the application of this analyte to early detection or screening programs. In the present investigation, we sought to compare serum PSA levels determined by the IMx assay (Abbott Laboratories, North Chicago, IL) and the Tandem E (Hybritech Inc., San Diego, CA) to determine whether there were differences. Two hundred twenty-eight random sera from our archival bank were investigated. One hundred-eight specimens were in the Tandem range of 2.0-10.0 ng/ml, and prostatic histology was known based on either systematic sector needle biopsy or transurethral resection. PSA was measured with three different lost of the IMx and Tandem assays. Over the entire range, there was a good correlation (r2 = 0.985); however, in the more useful clinical range of 2.0-10.0 ng/ml, the correlation was reduced to 0.923; in the 2.0-6.0 ng/ml range, it was further reduced to 0.852. The slope for the entire range was 0.948; however, in the 2.0- to 10.0-ng/ml range, it was 0.894; in the 2.0- to 6.0-ng/ml range, the slope was 0.815. Using PSA cutoffs of 4.0, 5.0, and 6.0 ng/ml, significant decrease in abnormal PSA values in men with cancer was observed with the IMx compared with Tandem. These data suggest that the IMx and the Tandem PSA assays are not equivalent, and in most patients a lower value is realized with the IMx assay. This bias appears to be greater in men with prostate cancer. Clinicians must be aware which assay their patients are being tested with, and laboratory technicians should run internal standards to ensure lack of significant intralot variability and consistency over time.

Humans↗