Eradication rate of Helicobacter pylori in a Mexican population at high risk for gastric cancer and use of serology to assess cure.
OBJECTIVE
Helicobacter pylori causes gastric adenocarcinoma. We assessed the success of H. pylori eradication therapy in a medically underserved population in Chiapas, Mexico, that is at high risk for gastric cancer risk.


METHODS
Healthy volunteers with both antibodies to CagA and gastrin levels > or = 25 ng/ml were randomly assigned to receive either a combination of omeprazole, amoxicillin, and clarithromycin or matched placebo for 1 wk. Endoscopy with seven biopsies was performed at baseline, at 6 wk, and 1 yr after treatment. Treatment success was defined as loss of H. pylori by histological analysis. Cure was assessed using change in serology based on the standardized absorbance of a H. pylori ELISA.


RESULTS
H. pylori eradication rates were high (intent-to-treat analysis: 76.3% [95% CI = 68.7-84.0%] after 6 wk and 76.1% [95% CI = 67.7-84.6%] after 1 yr; per protocol analysis: 77.8% [95% CI = 70.1-85.4%] after 6 wk and 75.2% [95% CI = 66.5-84.0%] after 1 yr). Nine subjects on active treatment and one subject on placebo who were without H. pylori at 6 wk were infected at 1 yr (recurrence rates 10.7% and 33.3%, respectively, p = 0.31). Median changes in standardized absorbance at 1 yr were 47% and 1% for successfully and unsuccessfully treated patients, respectively. A 10% decline in standardized absorbance after 1 yr had 84% sensitivity and 100% specificity for H. pylori eradication.


CONCLUSIONS
Even with a short course of treatment against H. pylori, a high rate of eradication rate can be achieved in populations at high risk for stomach cancer. Serum antibodies are useful in assessing efficacy of therapy.
Mohar
Alejandro
A
Instituto Nacional de Cancerología, Mexico City, Mexico.
Ley
Catherine
C
Guarner
Jeannette
J
Herrera-Goepfert
Roberto
R
Figueroa
Luz-Sánchez
LS
Halperin
David
D
Parsonnet
Julie
J
D000230:Adenocarcinoma / Q000209:etiology*; D000328:Adult; D000658:Amoxicillin / Q000008:administration & dosage; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D000897:Anti-Ulcer Agents / Q000008:administration & dosage; D000907:Antibodies, Bacterial / Q000032:analysis; D000942:Antigens, Bacterial / Q000032:analysis; D001426:Bacterial Proteins / Q000276:immunology / Q000378:metabolism; D017291:Clarithromycin / Q000008:administration & dosage; D004359:Drug Therapy, Combination; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005755:Gastrins / Q000097:blood; D005757:Gastritis, Atrophic / Q000188:drug therapy / Q000382:microbiology; D016481:Helicobacter Infections / Q000150:complications / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori / Q000276:immunology / Q000302:isolation & purification / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000008:administration & dosage; D010406:Penicillins / Q000008:administration & dosage; D011230:Precancerous Conditions / Q000188:drug therapy; D012372:ROC Curve; D012008:Recurrence; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000209:etiology*
D000900:Anti-Bacterial Agents; D000897:Anti-Ulcer Agents; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D005755:Gastrins; D007074:Immunoglobulin G; D010406:Penicillins; C080866:cagA protein, Helicobacter pylori; D000658:Amoxicillin; D017291:Clarithromycin; D009853:Omeprazole