Determination of a Cut-off Point for Prostatic Specific Antigen to Avoid Unjustified Biopsy Among Asymptomatic Elderly Men

Ibrahim, Afaf; Abou Khatwa, Samia; Atta, Mohamed; Ashry, Mona; Ismail, Asmaa

doi:10.21608/jhiph.2018.19956

Determination of a Cut-off Point for Prostatic Specific Antigen to Avoid Unjustified Biopsy Among Asymptomatic Elderly Men

Document Type : Original Article

Authors

¹ Community Medicine Department, Faculty of Medicine, Alexandria University, Egypt

² Uro-surgery Department, Faculty of Medicine, Alexandria University, Egypt

³ Family Medicine Physician, Ministry of Health, Egypt

10.21608/jhiph.2018.19956

Abstract

Background: To our knowledge, there is no national screening program for prostate cancer in Egypt. The Uro-surgery department in Alexandria University established a screening program for prostate cancer among men aged 55 years or more in January 2012.
Objective: To determine a valid Prostatic Specific Antigen (PSA) cut-off point for performing Transrectal Ultrasonography (TRUS) guided biopsy among asymptomatic elderly men.
Methods: A screening cross sectional study was conducted on a convenient sample of 1207 men aged ≥55 years who were attending urology department, Alexandria University for non-prostatic symptoms during years 2013 and 2014. Digital Rectal Examination (DRE) and PSA level measurement were performed for all included subjects. TRUS guided biopsy was done for those who found to have PSA ˃ 4ng/ ml and or suspicious DRE.
Results: Among subjects who had PSA level of 4.1-10, the Positive Predictive Value (PPV) for cancer prostate was 54% among those with suspicious DRE findings as compared to 0 among those with non-suspicious DRE. For PSA level of 10.1-20 and >20 with suspicious DRE, PPV was (77% and100% respectively). The mean serum total PSA was 77 and 0.6 ng/ ml for patients with and without prostatic cancer respectively (p= 0.0001). The yield of cancer prostate among all screened men was 103/1207= 8% and 103/157= 66% among those with PSA˃ 4 ng/ ml and or having suspicious DRE and were biopsied. Considering all men who had biopsy, ROC curve could derive a cut-off value of 10.05 ng/ml with a sensitivity of 92% and a specificity of 92.6%. Inability to perform biopsy for men with PSA ≤4 ng/ml was the main limitation.
Conclusion: In a country of relatively low prevalence of prostate cancer like Egypt, a cut-off point of PSA in combination with DRE for doing TRUS biopsy could be 10.05 ng/ ml among asymptomatic men ≥55 years of age with a likelihood ratio of 12.43.

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