This is an amazing story - and pretty much my worst nightmare. Not necessarily cancer itself, but the feeling and anxiety that you're not being treated and taken care of properly and that someone might be missing something. That doctors are (rightfully) unable to pay proper attention to everyone and everything just due to the sheer number of patients they must see. I know I'm prone to hypochondria, and it doesn't hel…
On the other hand, I agree that more data isn't necessarily better. There are plenty of examples. E.g.:
http://www.bloomberg.com/news/2012-05-21/prostate-cancer-tes...
If you do early prostate screening, you get worse medical outcomes than when you don't screen. Or consider whole-body scans:
http://www.radiologyinfo.org/en/news/newdetarget.cfm?ID=5
They will detect a lot of stuff that doesn't matter, but proving that it doesn't matter will be expensive and possibly harmful.
You see a similar phenomenon in investing. As Fooled by Randomness explains well, for most people the best strategy is to set your investments and look at them very rarely. If you watch the investment news all day and trade actively, you may not do better, you could easily do worse, and you'll certainly be much more stressed. But still, there is an endless supply of day-traders.