In order to prevent one death from the colorectal cancer among local people aged from 45 to 74 during the 14 years of follow-up, the NNI and NNBS for faecal occult-blood screening program were 1220 and 665, respectively.

• 通过计算得到欲通过实施FOBT筛检方案,要在14年内使当地45-74岁人群预防1例因结直肠癌所致的死亡,NNI为1220人,NNBS为665人;