Monday, August 2, 2010

PSA screening for Prostate Cancer

In the Lancet Oncology this week:

The results of a PSA screening trial is published from Sweden. 20,000 men were randomized between PSA screening every two years vs. no screening. With 14 years follow up, the number of men diagnosed with prostate cancer was 12.7% in the screened vs 8.4% in the non-screened populace. This translated to a HR of 1.64 (1.5-1.8 95% CI) for prostate cancer diagnosis. More importantly the HR for death of prostate cancer was 0.44 with screening (0.28-0.68 95% CI), though no difference was seen in overall survival. The number needed to screen (NNS) was 293, and the number needed to treat (NNT) was 12 to prevent one prostate cancer death. Not surprisingly the majority of the benefit was seen over 10 years out.

This is a higher reduction in risk than that seen in two prior studies (the ERSPC and the PLCO studies), so there is some conflicting data on this subject to be aware of (the ERSPC tiral was positive, but to a lesser degree, and the PLCO study was negative). The authors present a rationale for why the results were more pronounced in this study in their discussion.

[Articles] Mortality results from the Göteborg randomised population-based prostate-cancer screening trial: "Prostate cancer is one of the leading causes of death from malignant disease among men in the developed world. One strategy to decrease the risk of death from this disease is screening with prostate-specific antigen (PSA); however, the extent of benefit and harm with such screening is under continuous debate."

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