Determination of the “reflex range” and appropriate cutpoints for percent free prostatespecific antigen in 413 men referred for prostatic evaluation using the AxSYM system

Vashi, Apoorva; Wojno, Kirk J.; Henricks, Walter H.; England, Barry A.; Vessella, Robert L.; Lange, Paul H.; Wright, George L.; Schellhammer, Paul F.; Weigand, Ray A.; Olson, R M; Dowell, Barry L.; Borden, Kimberlee K.; Öesterling, Joseph E.

doi:10.1016/s0090-4295(96)00511-0

Cited by 110 publications

(45 citation statements)

References 30 publications

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“…A recent comparative evaluation of PSA density, PSA transition zone density, PSA velocity and the ratio fPSA to tPSA demonstrated that percent free PSA was the best discriminatory index between men with and without PCa. 5 Some studies proved the diagnostic power of the fPSA/tPSA ratio, 4,29,30 whereas other authors did not confirm its usefulness. 15,31 The reasons for these discrepancies are not known.…”

Section: Discussionmentioning

confidence: 99%

“…33 The use of the fPSA/tPSA ratio below the conventional limit of 4 g/l has already been recommended to improve either the sensitivity or specificity to detect patients with PCa. 5,30 Djavan et al 5 found that at the 95% sensitivity for PCa detection corresponding to a fPSA/tPSA ratio of 41%, 29.3% of unnecessary biopsies could have been avoided. Our data also showed that the use of the ratios in this low PSA range could help to eliminate about half of the unnecessary biopsies.…”

Section: Discussionmentioning

confidence: 99%

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Molecular forms of prostate-specific antigen in serum with concentrations of total prostate-specific antigen <4 ?g/L: Are they useful tools for early detection and screening of prostate cancer?

et al. 2001

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Molecular forms of prostate-specific antigen (PSA) improve the differentiation between benign prostatic hyperplasia (BPH) and prostate cancer (PCa) in men with total PSA concentrations between 4 and 10 g/l. To evaluate the diagnostic utility of free PSA (fPSA) and complexed PSA forms for identification of men with PCa in the low PSA range of <4 g/l, total PSA (tPSA), ␣ 1 -antichymotrypsin complexed PSA (PSA-ACT) and fPSA (Roche Elecsys [ES] system) as well as tPSA and complexed PSA (cPSA) (Bayer Immuno 1 system) were measured in archival serum samples from 31 untreated patients with PCa, 66 patients with BPH, and 90 men without prostatic disease. The median ratios of fPSA/tPSA, PSA-ACT/tPSA and cPSA/tPSA were significantly different between patients with BPH and PCa (27.2 vs. 19.4%, 64 vs. 88%, 77.2 vs. 88.2%, p < 0.05). No associations between PSA forms and tumor stage and grade were found. Analysis of the receiver operating characteristic curves showed that these ratios could discriminate better between BPH and PCa patients than determination of the analytes tPSA, fPSA, cPSA and PSA-ACT alone. The use of one of the ratios would have eliminated roughly half of the unnecessary biopsies in this study. The ratios should be considered as potential tools to increase the selectivity of PCa detection at low PSA concentration. The ratios fPSA/tPSA and cPSA/tPSA can be determined using commercially available assays so that one of these ratios could be preferred instead of PSA-ACT determination. The ratios could be useful in assessing the risk of PCa in the individual and therefore in deciding on prostate biopsy for final diagnosis.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Molecular forms of prostate-specific antigen in serum with concentrations of total prostate-specific antigen <4 ?g/L: Are they useful tools for early detection and screening of prostate cancer?

et al. 2001

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“…Both of these assays have been independently demonstrated to have acceptable within-run and between-day precision. 7,8 According to our study protocol, men with a F/T PSA ratio of 20% or less using either assay underwent 10-core prostate biopsy (including the standard sextant pattern and two additional cores on each side laterally directed in the anterior horns). A single pathologist reviewed all biopsy specimens.…”

Section: Methodsmentioning

confidence: 99%

“…Our screening protocol called for a prostate biopsy for men with a total PSA level of 3 to 10 ng/mL, only if the free/total (F/T) PSA ratio was 20% or less, which has been shown to significantly increase the specificity in this total PSA range. 6,7 We used the biopsy results to calculate the apparent sensitivity and specificity of the AxSYM and Immulite assays and to examine their concordance for prostate cancer detection.…”

mentioning

confidence: 99%

Assay Standardization Bias: Different Prostate Cancer Detection Rates and Clinical Outcomes Resulting from Different Assays for Free and Total Prostate-Specific Antigen

Sotelo

Mora

Pérez

et al. 2007

Urology

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OBJECTIVESNumerous commercial assays are available for measuring total and free prostate-specific antigen (PSA) levels in serum. These assays can be referenced to different laboratory standards, and interassay variability occurs. Patients and physicians might be affected by the variability between PSA assays that results from the use of different PSA standards. METHODSWe prospectively compared the free and total PSA measurements obtained using two commercially available PSA assays in 103 participants from a prostate cancer screening program in Caracas, Venezuela. We recommended biopsy to men with a total PSA level of 3 to 10 ng/mL and a free/total PSA ratio of 20% or less with either assay. We compared the sensitivity, specificity, and concordance index between the two assays to assess the effects of interassay variability on the cancer detection rate and clinical outcomes. RESULTSAlthough the total PSA results were similar between the assays, the free PSA level was significantly greater with one assay. Therefore, the free/total PSA ratio was discordant between the two assays, resulting in different biopsy recommendations and cancer detection rates. CONCLUSIONSUsing a free/total PSA ratio of 20% or less as the threshold for biopsy, the differences in assay sensitivity and specificity for detecting prostate cancer are significant. Commercially available assays for PSA and its derivatives are not necessarily interchangeable, and these differences might lead to different clinical outcomes. When using free and total PSA measurements to make clinical decisions, patients and physicians should be aware of the potential standardization bias and which assay is being used. UROLOGY 69: 1143-1146, 2007.

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“…Lower percent free PSA values are more suspicious for prostate cancer than higher values. [2][3][4][5][6][7] Free PSA may be useful in patients with moderately elevated PSA levels in whom a high percent free PSA suggests a benign source; it may help the clinician and patient to decide whether to proceed to transrectal ultrasound (TRUS)-guided prostate biopsy. 2,7 In addition to screening for prostate cancer, total PSA is used as a sensitive marker for prostate cancer recurrence At Princess Margaret Hospital, a tertiary cancer centre in Toronto, Ontario, Canada, all PSA results in the range of 4 to 10 ng/mL prompt the reflexive measurement of free PSA as an aid for timely availability of free PSA values when this test may be clinically useful.…”

Section: Introductionmentioning

confidence: 99%

Does the reflexive measurement of free PSA have a role in a tertiary cancer centre?

Allard

Yip

Blasutig

et al. 2013

CUAJ

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Purpose: The percent free prostate-specific antigen (PSA) may complement total PSA for prostate cancer screening, but is of no benefit for monitoring patients with previous prostate cancer diagnoses. At the Princess Margaret Hospital, a tertiary cancer centre in Toronto, Ontario, Canada, PSA values in the range 4 to 10 ng/mL prompt reflexive measurements of free PSA. We hypothesize that reflexive free PSA testing at tertiary cancer centres generates unnecessary costs as the test is often conducted on patients with previous diagnoses of prostate cancer. Materials and Methods:We reviewed all reflexive free PSA measurements conducted on a random sample of 250 men in a 10-year period at our institution. We determined the clinical indications for the PSA tests which triggered reflexive free PSA measurements to estimate the proportion of free PSA tests that are not clinically indicated. Results:We reviewed the 1099 reflexive free PSA measurements for the 250 subjects. Of these tests, 562 (51%) were triggered by PSA tests ordered for screening/early detection, and 537 (49%) for monitoring. Conclusions: Of all reflexive free PSA tests, 49% were unnecessary. We conducted 3022 free PSA tests, at a cost of $5.84 per test (Can$); the tests were performed in 2009 at this institution for a total cost of $17 648.48, about 49% of which ($8647.76) likely represents unnecessary annual costs. We suggest a trial of userselectable order sets allowing physicians to choose whether to include reflexive free PSA measurements on a case-by-case basis. This policy might improve the cost-effectiveness of the PSA test at tertiary cancer centres.Can Urol Assoc J 2010;4(5):317-320 RésuméObjectif : Le pourcentage d'antigène prostatique spécifique (APS) libre peut compléter la mesure de l'APS total dans le dépistage du cancer de la prostate, mais il n'est d'aucune utilité pour la surveillance de patients ayant déjà reçu un diagnostic de cancer de la prostate. À l'hôpital Princess Margaret, un centre de soins oncologiques tertiaires de Toronto, en Ontario (Canada), un taux d'APS se situant entre 4 et 10 ng/mL entraîne systématiquement une évaluation des taux d'APS libre. Nous avançons l'hypothèse que la mesure de l'APS libre dans les centres de soins oncologiques tertiaires entraîne des dépenses inutiles car ce test est souvent mené chez des patients ayant déjà reçu un diagnostic de cancer de la prostate.

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Determination of the “reflex range” and appropriate cutpoints for percent free prostatespecific antigen in 413 men referred for prostatic evaluation using the AxSYM system

Cited by 110 publications

References 30 publications

Molecular forms of prostate-specific antigen in serum with concentrations of total prostate-specific antigen <4 ?g/L: Are they useful tools for early detection and screening of prostate cancer?

Molecular forms of prostate-specific antigen in serum with concentrations of total prostate-specific antigen <4 ?g/L: Are they useful tools for early detection and screening of prostate cancer?

Assay Standardization Bias: Different Prostate Cancer Detection Rates and Clinical Outcomes Resulting from Different Assays for Free and Total Prostate-Specific Antigen

Does the reflexive measurement of free PSA have a role in a tertiary cancer centre?

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