Gastroscopy within 5 years before gastric-cancer diagnosis tied to lower mortality

Last Updated: 2017-07-19

By Lorraine L. Janeczko

NEW YORK (Reuters Health) - Gastroscopy five years or less before a diagnosis of gastric cancer is associated with lower mortality, new research from Taiwan shows.

"Our observations help establish clinical practice guidelines," Dr. Chun-Ying Wu of Taichung Veterans General Hospital in Taichung told Reuters Health by email.

"As endoscopists, we believe regular gastroscopy helps find early-stage-gastric-cancer patients and reduces mortality," he added. "There has been no good evidence to support this hypothesis, and our study fills the evidence gap. This is the first research to define the 5-year interval of gastroscopy to reduce gastric-cancer mortality in a gastric cancer median-risk country."

In a retrospective cohort study spanning a six-year period, Dr. Wu and his research team identified more than 20,000 newly diagnosed gastric cancer patients in Taiwan's National Health Insurance Research Database (NHIRD), which covers all residents.

Patients were matched into three cohorts according to the most recent gastroscopy before the date of gastric-cancer diagnosis: between six months and two years, between two and five years, and no gastroscopy within the past five years.

The three groups were matched for age, curative surgery for gastric cancer, Helicobacter pylori therapy, and propensity scores based on gender, comorbidities and medications.

After matching, the authors identified 1,286 patients who had gastroscopy between six months and two years prior to diagnosis, 1,286 who had the procedure between two and five years prior, and 5,144 with no gastroscopy in the past five years.

The researchers excluded patients with incomplete demographic data or other malignancies before the gastric cancer diagnosis and they retrieved the number and date of gastroscopies performed for any reason before the diagnosis of gastric cancer.

Because staging data were not available in the insurance database, they chose curative gastric-cancer surgery - total or subtotal gastrectomy with lymph node dissection - and chemotherapy as surrogates for cancer staging. All three groups were followed up from the date of cancer diagnosis to the date of death or the end of 2012.

Compared with the no-gastroscopy group, the hazard ratio (HR) of all-cause mortality for the six-months-to-two-years group was 0.80 (p<0.001); for the two-to-five-years group, it was 0.83 (p<0.001).

The gastric-cancer-specific mortality hazard ratios were also significantly lower in the two groups.

Dr. Wu pointed out several strengths of the study. First, the nationwide cohort study design avoided potential selection bias. Second, the study used overall mortality, instead of cancer stage, as the outcome. Third, this was the first study using a gastric-cancer median-risk population, rather than high-risk populations, such as in Korea or Japan, so it has better external validity to apply to worldwide populations.

Dr. Wu also acknowledged several limitations, including that the observational study does not reveal the mechanisms underlying the reduced mortality seen with more-recent gastroscopy; that some clinically important information such as gastroscopy finding, pathology reports, and image results, were not available; and that the severity and reversibility of these illnesses were difficult to determine.

He recommended further research to stratify patient risk based on personal factors that will enable personalized precision medicine to reduce gastric cancer deaths.

Dr. Joseph Chao of City of Hope Comprehensive Cancer Center in Duarte, California, told Reuters Health by email, "This study provides some support that patient mortality can be reduced by more-frequent diagnostic endoscopies leading up to the index endoscopy that ultimately provides a gastric cancer diagnosis."

"This study was limited to a Taiwanese patient population, and the results may not be directly translatable to a Western/European patient population where gastric cancer diagnoses are lower in incidence, compared to Asian patients," added Dr. Chao, who was not involved in the study. "Also, it is not entirely clear whether the diagnosis of gastric cancer at earlier stages or other unexplained mechanisms accounted for the observed reduced patient mortality."

SOURCE: http://bit.ly/2vBrr7v

Gastrointest Endosc 2017.