i posted in July (see here) about the likely utility of treating asymptomatic h pylori infections in high risk populations to decrease the risk of gastric cancer. there has been a subsequent systematic Cochrane review in the BMJ on this subject (see doi: 10.1136/bmj.g3174). 6 RCTs were identified, with inclusion criteria including using eradication therapy at least 7 days and minimum of 2 years of followup. primary outcome of occurrence of gastric cancer. results:
–all but one study conducted in East Asia (other in Colombia), so hard to assess effect in Western populations. only one study with longer-term followup (14.7 years). h pylori eradication rates in low 70% range|
–51 (1.6%) gastric cancers in those receiving eradication therapy vs 76 (2.4%) in 3203 control patients, for RR 0.66. with assumption that eradication leads to lifelong benefit, the number needed to treat varies from 15 for Chinese men to 245 for US women (this is based on life-time risk of gastric cancer).
–of these gastric cancers, there was only one case of MALT lymphoma (not included in analysis)
–only 3 cases of esophageal cancer, so no significant difference
–only difference in adverse effects was rash in 3.1% on eradication therapy vs 0.1% on placebo
seems to me that the assumption of lifelong protection from h pylori eradication (ie, not get recurrent infection) is borne out by other studies. as noted in blog below, the benefit of eradicating the h pylori infection was in those without precancerous lesions at the time, which suggests that longer followup might yield even better gastric cancer prevention. so, to me this reinforces the comment to test and treat asymptomatic patients who come from high prevalence h pylori countries (which also seems to track with those at higher risk of gastric cancer).
geoff