Plasma gastrin concentrations are normal in patients with colorectal neoplasia and unaltered following tumor resection.

BACKGROUND/AIMS: Previous studies have found that colorectal cancer patients have hypergastrinemia, but most have been inadequately controlled. Preoperative fasting and meal-stimulated gastrin levels were measured in patients with colorectal tumors (n = 42) and in carefully matched controls (n = 34). Helicobacter pylori status was assessed because it causes significant hypergastrinemia.

METHODS

Plasma gastrin levels were measured by radioimmunoassay. Helicobacter status was assessed using the [14C]urea breath test and serology (immunoglobulin G).

RESULTS

Preoperatively, fasting plasma gastrin levels were similar in patients with tumors (median, 55 ng/L; interquartile range, 45-82.5) and controls (77.5 ng/L; 53.7-137.5; P = 0.10). Similarly, peak gastrin levels were not significantly different in tumor patients (200 ng/L; 137.5-312.5) and controls (247.5 ng/L; 147.5-375; P = 0.21). The prevalence of H. pylori infection in patients with tumors (60%) and controls (53%) was similar in both groups. Five (20%) tumor patients who were H. pylori-positive preoperatively were negative postoperatively, and their median peak plasma gastrin level decreased from 200 ng/L to 140 ng/L. After these patients were excluded, fasting and peak plasma gastrin concentrations were similar preoperatively and postoperatively.

CONCLUSIONS

When confounding factors are controlled for, plasma gastrin levels are not increased in colorectal cancer and do not decrease after curative resection. Previously noted decreases in gastrin levels after tumor resection may be attributable to loss of H. pylori infection in some patients, as noted here.