Of the 854 patients who underwent randomization , 33 ( 3.9 % ) had a new diagnosis of occult cancer between randomization and the 1-year follow-up : 14 of the 431 patients ( 3.2 % ) in the limited-screening group and 19 of the 423 patients ( 4.5 % ) in the limited-screening-plus-CT group ( P = 0.28 ) .