Thomas Tran

OBJECTIVES: The epidemiology of gastrointestinal stromal tumor has not been well examined, and prior studies often provide conflicting results. We conducted the first population-based study to evaluate the incidence and survival of malignant gastrointestinal stromal tumor in the United States. METHODS: We utilized the Surveillance, Epidemiology, and End Results registry from the National Cancer Institute to identify all cases of malignant gastrointestinal stromal tumor diagnosed from 1992 to 2000. The age-adjusted incidence rates and the survival rates were calculated. Cox proportional hazards models were used to examine the risk of mortality. RESULTS: Between 1992 and 2000, there were 1,458 cases of diagnosed gastrointestinal stromal tumor. The age-adjusted yearly incidence rate was 0.68/100,000. The mean age at diagnosis was 63 yr. Fifty-four percent were men and 46% were women. The incidence rate was higher among men and among Blacks. Fifty-one percent of cases were in the stomach, 36% small intestine, 7% colon, 5% rectum, and 1% in the esophagus. Fifty-three percent of cases were staged as localized, 19% regional, 23% distant, and 5% unstaged. The 1- and 5-yr relative survival rates were 80% and 45%, respectively. The Cox analysis showed that older age, Black race, advanced stage, and receipt of therapy were independent predictors of mortality. CONCLUSIONS: Malignant gastrointestinal stromal tumors rare, but are more common in the older population, men, and Blacks. Risk factors for mortality include older age, Black race, advanced stage, and no surgical intervention.

OBJECTIVE: Obesity may increase intra-abdominal pressure on the stomach leading to an increase in intragastric pressure, which in turn induces lower esophageal sphincter relaxation, with subsequent reflux. However, the association between anthropometric measures of total body as well as abdominal obesity and intragastric pressure has not been examined. MATERIAL AND METHODS: This prospective cross-sectional study included consecutive patients undergoing manometry at an open access Reflux Center. Standardized measurements of body-weight, height, and waist and hip circumference were prospectively obtained. To assess the intragastric pressure, the perfusion port levels of the catheter were verified to be at the same vertical height (0 mmHg) inside the patient as they were outside the patient during calibration. Correlation between gastric pressure and anthropometric measures was calculated and adjusted for demographic features and presenting symptoms. RESULTS: A total of 322 patients (67% women) with a mean age of 52.5 years were enrolled. The mean values for weight, height, and body mass index (BMI) were 77.2 kg, 168 cm, and 27.5 kg/m2, respectively (range 16.0-52.0, median 27.0). The mean intragastric pressure was 2.9 cm H2O (SD: 1.7). There was a weak, positive correlation between gastric pressure and both BMI (r=0.11, p=0.05) and waist circumference (r=0.11, p=0.06). The associations between gastric pressure and both BMI and waist circumference were relatively unaffected by adjusting for several variables including age, indications for manometry, race, and gender in a multivariable linear regression model. For each unit increase in BMI, there was approximately a 10% increase in intragastric pressure. CONCLUSIONS: In this study of consecutive patients with wide-ranging BMI values, there was a weak, positive correlation between intragastric pressure and both BMI and waist circumference. This indicates that obesity operates to increase the risk of gastroesophageal reflux disease (GERD) at least partly by increasing intragastric pressure.

BACKGROUND AND AIMS: It has been proposed that fundoplication can reduce the risk of esophageal cancer in patients with gastroesophageal reflux disease (GERD). In this cohort study, we assessed the effect of fundoplication on the incidence of esophageal cancer. METHODS: We identified all Veterans Affairs (VA) patients with GERD who had fundoplication between 1986 and 1990 and matched (1-2) to controls with GERD and no fundoplication and to controls with no GERD. We calculated incidence rates for esophageal cancer through October 2002 and examined the effect of fundoplication on the risk of esophageal cancer using Kaplan-Meier survival analysis and Cox proportional hazard analysis. We calculated and adjusted for the propensity score for receiving fundoplication. RESULTS: We identified 946 patients who had fundoplication, 1,892 patients who had GERD without fundoplication, and 5,676 patients with no GERD. The mean age was 55 yr and 97.5% were men in all three groups. During a follow-up of 11,156 patient-years (PY), there were eight cases of esophageal cancer (72/100,000) in the fundoplication group. During a follow-up of 20,115 PY, there were eight cases of esophageal cancer (40/100,000) in the GERD without fundoplication group. During a follow-up of 59,439 PY, no patients in the group with no GERD developed esophageal cancer. The Kaplan-Meier analysis showed no significant difference in cumulative esophageal cancer rates between the fundoplication group and the GERD no-fundoplication group. The adjusted hazard ratio of esophageal cancer with fundoplication was 1.88 (95% CI: 0.70-5.03). CONCLUSIONS: GERD is a risk factor for esophageal cancer, but there is insufficient evidence that fundoplication reduces that risk.