John Ioannidis: "Screening for diseases that can lead to death typically does not prolong life substantially; a few screening tests may avert some deaths caused by the disease being screened, but even then it is difficult to document an improvement in overall survival"

http://scopeblog.stanford.edu/2015/01/15/screening-for-diseases-doesnt-necessarily-save-lives-study-shows

 http://ije.oxfordjournals.org/content/early/2015/01/14/ije.dyu140.full