Very much a chicken/egg problem. >The effectiveness of screening for a given disease before signs and symptoms appear depends on a host of conditions... includ

Very much a chicken/egg problem. >The effectiveness of screening for a given disease before signs and symptoms appear depends on a host of conditions... including whether there’s an effective treatment for whatever is found... There are so very few ways to even think about, treat, or even test for the earliest stages of a disease precisely because we don't have data about the early stages. Getting that data would certainly provide for data upon which to design better early-stage therapies. The use of measuring PSA (as mentioned) works great in more advanced stages of prostate cancer, and probably doesn't work well for early stages - but if we had good and regular testing we could find an indicator for those early stages. So which comes first, the readout, or the therapy? Of course, it's the readout. Just because we don't have those new early-stage-targeting therapies yet doesn't mean a new array of (accurate and reliable) testing wouldn't be extraordinarily helpful.