As reported in Amendment 1, the trial was stopped in May 2010 after the enrolment of 313 patients, which was the minimum sample size calculated in order to achieve a 80% power of detecting a difference in the primary-endpoint rate from 40% in the conservative arm to 25% in the invasive arm, based upon the log-rank test for survival curves (1-beta 0.80; 2-tailed alpha 0.05)