Prostate-Specific Antigen /Blood Clinical Trial
Official title:
Study of the Adequacy of the Requests of Prostate-Specific Antigen (PSA), Factors Associated With the False Negative and Positive Results and the Impact on Patient's Health
Objectives:
The primary aim of this study is to evaluate the outcomes of the determination of PSA for the
early detection of prostate cancer or in the presence of symptoms, in general practice in two
health departments of the Valencian Community (Spain).
Specific objectives:
1. To analyse the clinical and analytical factors associated with the presence of false
positive and false negative results in PSA determinations in patients within the setting
of opportunistic screening and in those with symptoms.
2. To evaluate the patient's clinical outcome, diagnostic and/or clinical and/or
therapeutic interventions implemented in each patient according to the PSA value and the
patient's clinical variables during the two years of follow-up. Furthermore, the
investigadors will study whether this management is appropriate to the recommendations
of the European Society of Urology.
Sample size and recruitment procedure:
The investigators will select a cohort of patients with positive PSA results and a cohort of
patients with negative results in each centre, to be followed for two years.
According to a review by the American Cancer Society, a value of PSA of 4 ng/ml had an
estimated sensitivity of 21% to detect any type of prostate cancer and a specificity of 91%.
The investigators estimate a prevalence of prostate cancer in this population not lower than
5% (given that the investigators include asymptomatic and symptomatic patients), with a 95%
margin of error and 2% precision, the investigators will need to include 457 patients with a
negative PSA result and 865 PSA-positive patients. Taking into account a 20% possible loss
during follow-up, the investigators will increase to 572 patients with a negative PSA result
(286 per centre) and 1,081 patients with a positive PSA result (541 per centre) who will be
selected consecutively from among those included in the cross-sectional study until the
investigators reach the proposed sample size. The investigators will use the initial
randomized list (which included determinations during the first 6 months of 2018) to select
patients who meet both negative and positive PSA criteria and if it is necessary, the
investigators will continue to review analyses until the sample size is achieved.
Data collection procedure:
The investigators will follow both cohorts (positive and negative PSA results) for two years
by reviewing their medical records (every 3 months for patients with a positive PSA result
and annually for patients with a negative result). The following variables will be recorded:
sociodemographic and clinical characteristics (patient who has the PSA determination as part
of opportunistic screening or due to the presence of symptoms suggestive of disease), other
comorbidities, toxic habits, previous history of cancer, family history, present
pharmacological treatment and setting.
The investigators will evaluate the presence of false positive and negative results according
to the latest recommendations of the European Association of Urology (specific objective 1).
The interventions performed after PSA determination and until the follow-up deadline, and
their adaptation to the latest available recommendations (specific objective 2) will be
evaluated separately by at least two investigators.
Data analysis plan The analysis will be performed using the Stata IC 15 program.
- Specific objective 1. The investigators will calculate the proportion of false positive
and false negative results for the diagnosis of PCa and the associated variables. In the
case of false positive tests, the investigators will also describe the time from a
positive PSA result until PCa is ruled out using mean, standard deviation or median and
interquartile ranges for the total population and relevant subgroups.
- Specific objective 2. The investigators will assess the probability of having a
diagnostic, surgical or therapeutic intervention according to variables using risk ratio
(statistical precision as for specific objective 1). If necessary, the investigators
will use log-binomial regression estimating prevalence ratios. the investigators will
also evaluate the agreement between the interventions performed and the available
guidelines.
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