The latent period before an effect on deaths was about 5 years
for oesophageal, pancreatic, brain, and lung
cancer, but was more delayed
for stomach, colorectal, and prostate cancer. For lung and oesophageal cancer, benefit was confined to adenocarcinomas, and the overall effect on 20-year risk of cancer death was greatest for adenocarcinomas (HR 0·66, 0·56—0·77, p<0·0001).