Pattern of use of prostate-specific antigen (PSA) among different clinical specialties : retrospective study in a tertiary hospital

Abstract

Background The Urology Specialist Outpatient Clinic (SOPC) at Queen Mary Hospital frequently receives many referrals for raised prostate specific antigen (PSA). However, many patients are elderly with life expectancy of less than 10 years. Moreover, a large majority did not understand the significance of a raised PSA. Some were not even aware that PSA level was checked. In view of the increasing number of referrals for raised PSA in elderly patients, we studied the reason behind why PSA was checked initially, to see whether it was clinically indicated, and to study whether the checking of PSA affected patient management. Methods This was a single center retrospective cross sectional study. All patients who had PSA checked from 1 January 2014 to 31 March 2014 by the laboratory of the Division of Immunology at Queen Mary Hospital were recruited into the study. Clinical records of patients were traced and reviewed using a standard proforma. Demographics of the patient, requesting specialty, indications and clinical circumstances under which PSA was performed, any contraindications for checking PSA were noted. Results of the PSA test and subsequent clinical outcome of the patient were also followed up. All patients with known carcinoma of the prostate were excluded from the analysis. Questions of interest included proportion of different specialties requesting PSA tests, indications of checking PSA, outcomes of patients with raised PSA and treatment choices of patients diagnosed to have prostate cancer. The aim of this study is to explore whether there was an unreasonable use of PSA testing and whether the problem of over diagnosis existed, and to what extent it would result in overtreatment. Results There were a total of 2104 PSA requests over the three month period. Mean age of patients was 69.6 years old (range 19-99, SD 11.7). Mean PSA level was 36.37ng /ml (range <0.1 to 4517, SD 226.9). Median PSA level was 2.7 ng/ml. 429 (20.4%, /2014) patients had raised PSA levels > 4 ng/ml, with no prior history of prostate cancer. 386 patients (90%, /429) were seen at the Urology Clinic for further management. Doctors performed digital rectal examination in 315 (73%, /429) of patients. 128 (29.8%, /429) patients underwent trans-rectal ultrasound guided prostate biopsy (TRUS Bx). 49 patients (38%, /128) were diagnosed to have prostate cancer. 23 patients (46.9%, /49) opted for radical treatment for prostate cancer. 10 (43.5%, /23) underwent radical prostatectomy and 13 (56.5%, /23) had radiotherapy. Logistic analysis showed that age and stage of disease was significantly higher in patients who underwent radiotherapy. Only age was shown to be a statistically significant predictor for pick-up of prostate cancer (p=0.001). All other factors including PSA level, requesting specialty and indications for checking PSA were not predictors for detection of prostate cancer. Conclusion PSA screening is a controversial topic. The latest international guidelines do not advocate PSA screening in the general population. Inappropriate PSA testing is widespread at our institute, with over one third of requests not supported by any relevant clinical information. The pick-up rate of prostate cancer is only 1.7%, which is very low. Even for patients diagnosed to have local prostate cancer, less than two thirds of patients opted to have radical treatment. Patient counseling is important prior to checking of PSA. Patients should understand that PSA screening is a controversial issue and to understand the implications of raised PSA levels. Health professionals need to make shared decisions with the well-informed patient prior to checking PSA.