Date Published: April 16, 2019
Publisher: Public Library of Science
Author(s): Janet Bouttell, Jeremy Teoh, Peter K. Chiu, Kevin S. Chan, Chi-Fai Ng, Robert Heggie, Neil Hawkins, Neal Shore.
A recent study showed that the Prostate Health Index may avoid unnecessary biopsies in men with prostate specific antigen 4-10ng/ml and normal digital rectal examination in the diagnosis of prostate cancer in Hong Kong. This study aimed to conduct an economic evaluation of the impact of adopting this commercially-available test in the Hong Kong public health service to determine whether further research is justified. A cost-consequence analysis was undertaken comparing the current diagnostic pathway with a proposed diagnostic pathway using the Prostate Health Index. Data for the model was taken from a prospective cohort study recruited at a single-institution and micro-costing studies. Using a cut off PHI score of 35 to avoid biopsy would cost HK$3,000 and save HK$7,988 per patient in biopsy costs and HK$511 from a reduction in biopsy-related adverse events. The net cost impact of the change was estimated to be HK$5,500 under base case assumptions. At the base case sensitivity and specificity for all grades of cancer (61.3% and 77.5% respectively) all grade cancer could be missed in 4.22% of the population and high grade cancer in 0.53%. The introduction of the prostate health index into the diagnostic pathway for prostate cancer in Hong Kong has the potential to reduce biopsies, biopsy costs and biopsy-related adverse events. Policy makers should consider the clinical and economic impact of this proposal.
Prostate Cancer (PCa) is the second most commonly diagnosed cancer in men worldwide . The incidence of PCa in Chinese men is 10 times lower than the rate in men from Western Europe but it has increased rapidly in recent years [2,3]. Positive biopsy rates are lower in Asian men (15–25%) compared with Western European men (30%) and cancer tends to be diagnosed later [2,3]. The first steps on the current diagnostic pathway in Hong Kong to evaluate for PCa is a digital rectal examination (DRE) and the prostate specific antigen (PSA) blood test. In men whose DRE is normal but whose PSA levels are between 4–10 ng/ml the current diagnostic pathway requires a transrectal ultrasound-guided (TRUS) biopsy. Such biopsies are invasive and carry considerable risks of post-procedure complications including infection, fever, acute urinary retention, haematuria and haemospermia. As positive biopsy rates are low, many biopsies are carried out unnecessarily under the current diagnostic set-up .
Our base-case analysis uses a PHI score of 35 as this was considered the most likely cut-off level to be acceptable to decision-makers. The introduction of the PHI test at a cut-off of 35 into the diagnostic pathway for men with normal DRE and PSA levels 4–10 ng/ml would save an estimated HK$5,500 per patient (see Table 2). The majority of the saving results from approximately 75% of patients avoiding TRUS biopsy as their PHI score was under 35. A further cost saving of HK$511 per patient results from a reduction in adverse events following biopsies. If the cut-off for PHI testing was increased to 55 over 95% of biopsies could be avoided resulting in an overall cost saving estimated to be in excess of HK$8,000 per patient. At this cut-off level cost savings are reduced to HK$914. At all cut-off levels the introduction of PHI results in cost savings although these are greater at higher cut-off levels as more biopsies are avoided. Testing costs for PHI are included in the analysis at HK$3,000 and it is proposed to test all patients in this population. Testing costs may reduce under the new testing strategy as a result of increased volumes. This has not been reflected in the base-case analysis although test cost is varied in the sensitivity and threshold analyses.
The immediate implication of this study for policy-makers is that in the Hong Kong context PHI is likely to be a cost-saving addition to the diagnostic set-up for prostate cancer in men with PSA levels of 4-10ng/ml and negative DRE. Although health outcomes have not been fully quantified, the analysis suggests that, at the proposed cut off of 35, sensitivity could be retained such that all grade cancer would be missed in 4.2% of the population (and high grade cancer in 0.53%) whilst a high proportion of biopsies would be avoided. The use of the PHI test in Hong Kong appears to warrant further investigation, particularly with regard to the level of missed cases and the longer term health outcomes in these cases. Policy makers in other jurisdictions may also wish to evaluate the use of Prostate Health Index in the diagnosis of prostate cancer particularly in Asian populations where the prevalence of prostate cancer is relatively low .