The worldwide decline in prostate cancer mortality¹ is more pronounced in countries where screening is more common, such as the USA², and is mostly attributed to the reduction in numbers of men who present with metastatic disease. Screening also advances diagnosis by 5-13 years, which leads to a significant stage migration when cure is more likely³.

Prostatectomy or radiotherapy for early prostate cancer has favourable outcomes⁴. The combination of prostate cancer screening and aggressive early treatment can reduce prostate cancer mortality⁵. Since early stage prostate cancer is asymptomatic, and only organ-confined disease can be cured, it would seem obvious that prostate cancer screening should become routine.

Unfortunately, while PSA testing has a reasonable sensitivity of 70-80% at the normal “cutoff” of 4ng/ml, its specificity is low. In addition, the optimal re-screening interval is unknown⁶. Over-diagnosis with ‘clinically-irrelevant’ cancers plagues every screening program, including prostate cancer. The impact of age and co-morbidities on the management of prostate cancer in terms of quality of life and cost-effectiveness is unresolved. Since the criteria for conservative management in early prostate cancer is as yet not well defined, over-treatment for some is inevitable.

Nevertheless, the American Cancer Society⁷ and American Urological Association (AUA) have recommended screening with PSA and digital rectal examination for men with a life expectancy of at least 10 years, from the age of 50 years. Informed consent for PSA testing includes the potential risks and benefits of screening and treatment.

Recently, the US Preventive Services Task Force had found insufficient evidence for or against routine screening for prostate cancer⁸. The Singapore Urological Association (SUA) does not recommend screening amongst Asian men. As a screening tool PSA testing is a controversial issue. However, its role as an aid to early diagnosis is more acceptable, including the European Association of Urology.

The AUA recommends PSA screening in high risk patients with a positive family history of prostate cancer from age 45 years old⁹. The SUA also recommends screening in men having a first-degree relative with prostate cancer diagnosed before 60 years old.

In this current climate of uncertainty, the healthcare provider should adopt an “impartial” stance. We should neither actively promote nor dissuade screening, but rather adequately inform and involve them in the decision-making process¹⁰.

In 2004, we found 255 men with PSA > 4 ng/ml amongst the 3646 participants for the inaugural prostate awareness week organized by the SUA. Prostate cancer was found in 39 of 159 prostatic biopsies performed.

All eyes are on the outcomes of ongoing randomized trials that may provide the final verdict on prostate cancer screening^11,12. Ultimately, the truth may hinge on research into a biomarker that can reliably identify “clinically relevant” cancers. To renounce PSA testing and return to the pre-PSA era when most cancers were incurable at diagnosis is not an option. As such, PSA screening remains relevant, and emerging evidence from clinical and basic research will only strengthen its position.

Henry Ho, Weber Lau KO, Chong TW, Christopher Cheng
Department of Urology, Singapore General Hospital


Reference

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