This is regarding a 41-year-old gentleman who happened to have H-pylori infection in the past and was given a course of eradication treatment.
The only way to check whether he has still got H-pylori infection is either to do another Oesophago-gastro-duodenoscopy and take biopsies for H-pylori infection or do a breath test. Unless there is still evidence of infection being there, he should not take any more antibiotics.
As far as his concern regarding stomach cancer, I think it is very unlikely that he will develop stomach cancer. However it is important to eradicate H-pylori. Hence I feel he should rest assured that he will not develop cancer if the H-pylori is negative.