Critical appraisal:Thompson IM, Ankerst DP, Chi C, Goodman PJ, Tangen CM, Lucia MS, et al 2006
From Cancer Guidelines Wiki
Risk of bias assessment: diagnostic accuracy study
Patient Selection
Prior tests and any referral filters
- PSA, DRE and AUA <20
Condition that defined entry into study
- PSA less than or equal to 3.0ng/mL, normal DRE AUA <20 and 2 PSA tests in 3 years prior to biopsy
Setting
- multi centre RCT
Was a diagnostic case-control design avoided?
- Yes
Consecutive or random sample?
- Unclear
Did the study avoid inappropriate exclusions?
- Yes
Reasons
- excluded men with no PSA test < 1 year prior to biopsy or who had less than 2 PSA tests in prior 3 years ( men diagnosed with prostate cancer in earlier years and men who were not compliant) - unlikely to cause bias?
If comparing more than one index test was the design fully paired or paired randomly?
- Yes
If a paired randomised design was used, was allocation to groups concealed and was the generation of allocation sequence adequate?
- Not applicable
What is the risk that the selection of participants introduced bias?
- Low
Comments
Index test 1
Describe index test and how it was conducted and interpreted
- various PSA levels
Were the index test results interpreted without knowledge of the results of the reference standard?
- Yes
If a threshold was used, was it pre-specified?
- No
If two tests are being compared, have they been assessed independently / blind to each other?
- Yes
What is the risk that the conduct or interpretation of the index test introduced bias?
- Low
Comments
- Lack of pre-specified threshold unlikely to cause bias in this instance
Index test 2
Describe index test and how it was conducted and interpreted, if applicable
- PSA greater or equal to 4.0 ng/mL
Were the index test results interpreted without knowledge of the results of the reference standard?
- Yes
If a threshold was used, was it pre-specified?
- Yes
What is the risk that the conduct or interpretation of the index test introduced bias?
- Low
Comments
Reference Standard
Describe the reference standard and how it was conducted and interpreted
- sextant biopsy 84.5% of men with PSA<4.0 had sextant biopsy
Is the reference standard likely to correctly classify the target condition?
- No
Were the reference standard results interpreted without knowedge of the results of the index test/s?
- Unclear
Was the reference test standard independent of the index test?
(i.e. the index test did not form part of the reference standard)
(i.e. the index test did not form part of the reference standard)
- Yes
What is the risk that the reference standard, its conduct or interpretation introduced bias?
- High
Comments
- Reference standard may have missed some cancers
Flow and timing
Describe any patients who did not receive the index test(s) and/or reference standard or who were excluded from the 2x2 table
- all men biopsied regardless of PSA at end of study - during study annual screening with biopsy if abnormal DRE or PSA greater or equal to 4.0ng/mL
Describe the time interval and any interventions between index test(s) and reference standard
- less than 1 year
If a predictive test (the reference standard is a later event that the test aims to predict) were any subsequent interventions between test and later event blind to test result?
- Not applicable
Was there an appropriate interval between index test(s) and reference standard?
- Yes
Did either all participants or a random sample of participants receive a reference standard test?
- Yes
Did all patients receive the same reference standard irrespective of index test result?
- Yes
Were all test results including unclear results reported?
- Unclear
Were all patients included in the analysis?
- No
What is the risk that the patient flow introduced bias?
- Low
Comments
- 65.2% of men underwent biopsy - imputed values for remaining 44.8% - results very similar whether include imputed values or not - so fact not all patients included in analysis not a problem
Overall risk of bias
| At risk of bias | Additional comments: Please replace this text and include any additional comments in regards to your quality rating |
This appraisal has been completed.
- Article
- Thompson IM, Ankerst DP, Chi C, Goodman PJ, Tangen CM, Lucia MS, et al. Assessing prostate cancer risk: results from the Prostate Cancer Prevention Trial. J Natl Cancer Inst 2006 Apr 19;98(8):529-34 Available from: http://www.ncbi.nlm.nih.gov/pubmed/16622122.
- Assigned to
- User:Suzanne.hughes
- Topic area
- Guidelines:PSA Testing/PSA Protocols
- Clinical question
Section below only relevant for Cancer Council Project Officer