许先生今年52岁,是一名司机。近两年来,他经常出现上腹部隐痛不适、嗳气的症状,有时在进餐后还会发生呕吐。他曾先后两次去某医院做胃镜检查,均被诊断患有慢性胃炎。许先生吃了很多治疗慢性胃炎的药,但没有取得明显的效果。三个月前,他来我院进行腹部CT检查时,医生怀疑他患有胃癌。经做手术探查,医生确诊他患有胃体胃癌。许先生十分难过和不解:他曾做过两次胃镜检查,那时为何没查出患有胃癌呢? Mr. Xu is 52 years old and is a driver. In the past two years, he often has symptoms of abdominal discomfort, suffocation, and sometimes vomiting after eating. He once went to a hospital for gastroscopy twice and was diagnosed with chronic gastritis. Mr. Xu had eaten many medicines for treating chronic gastritis, but he had not achieved obvious results. Three months ago, when he came to our hospital for abdominal CT examination, the doctor suspected that he had stomach cancer. After surgery, the doctor confirmed that he had stomach cancer. Mr. Xu is very sad and puzzled: he had done two gastroscopy, why did he not find out that he had stomach cancer?