“False positive” data from the European screening trial and other matters

This article is again nicked from The "New" Prostate Cancer InfoLink so I hope they don't mind.I've only copied part of their article but the link for the full text is below:

"The “game” of retrospectively analyzing every possible piece of data from the European Randomized Screening Study for Prostate Cancer (ERSPC) has been under way for a while now … and we can expect this game to produce lots and lots of controversial information and media coverage. But much of the data from these subset analyses will need to be treated with great caution.
Let’s look at just two current examples.

A new analysis of data from the Finnish section of the trial (where the men received a PSA test once every 4 years) has claimed that for every eight Finnish men who met the criteria for a biopsy, one man had a “false positive” result. But if you read even the abstract of the actual paper, you wonder whether this is really what the authors meant to state."


"The researchers defined a false positive result as “a positive screening result without cancer in [biopsy cores taken] within 1 year from the screening test.” But why on Earth would one define this as a “false positive” result? It is well understood that PSA levels rise for all sorts of reasons. It is perhaps shocking that as many as 7 men in 8 out of all those biopsied in Finland in this trial would have had a positive biopsy result! It is the biopsy that defines a diagnosis of cancer, not the PSA test. The PSA test only indicates the possibility of the cancer!"

“False positive” data from the European screening trial and other matters