Take 1000 men over the age of 50 and give them PSA and DRA for about 15 years. Take 1000 other men over 50 don't give them PSA nor DRA over the same time.

> About 10 out of every 1,000 men with screening, and 12 out of every 1,000 men without screening died from prostate cancer within 16 years. This means that 2 out of every 1,000 people could be saved from death from prostate cancer by early detection using PSA testing. This was not reflected in overall mortality.

Over all about 322 men died in both groups, so it doesn't seem to make much difference to all cause mortality.

However, in the group who was screened we see 155 people had a false alarm (and that includes unnecessary tissue removal), and 51 men with non-progressive cancer had unnecessary treatment (that sometimes includes impotence or incontinence).

The most important question you can ask a doctor is what happens if we don't do this?

There are different types of prostate cancer. Some are very slow growing and people tend to die with it, not of it. There are aggressive types of prostate cancer that do kill people, but these tend not to be found in time to make much difference to populations at the moment.