Diagnosis and t-staging of gastric cancer: comparison of standard computed tomography and computed-tomographic pneumogastrography

The advantages of computed tomographic pneumogastrography with the possibility of three-dimensional visualization and virtual gastroscopy in diagnosing gastric cancer are considered. The study included 479 patients with histologically diagnosed gastric cancer who were treated at the National Medical Research Center of Oncology named after N.N. Petrov from 2011 to 2018. 232 patients received preoperative chemotherapy. All patients underwent surgery: 70 —in the volume of endoscopic dissection, 40 — proximal subtotal resection, 166 — distal subtotal resection, 203 — gastrectomy. All patients at the preoperative stage underwent staging computed tomography on a 64-slice X-ray computed tomograph: 208 patients underwent computed tomography according to the standard protocol without targeted preparation of the stomach for the study, 271 patients with targeted preparation of the stomach for the study according to the computed tomographic pneumogastrography protocol. The sensitivity of the computed tomography in assessing the T-stage was assessed by comparison with pathomorphological data. Of the 208 patients who underwent computed tomography according to the standard protocol, a gastric cancer was detected in 111 (53.4%), out of 271 patients who underwent computed tomography pneumogastrography, a gastric cancer was detected in 267 (98.52%), which is a statistically significant difference in comparing computed tomography methods (Pearson, χ² — 144.223, df = 1; p < 0.001). There are statistically significant differences when comparing computed tomography according to the standard protocol and computed tomographic pneumogastrography in detecting gastric cancer for all tumor categories: T/yT1 — 8.2 and 94.4% (Pearson, χ² — 99.205, df = 1; p < 0.001), T/yT2 — 47.8 and 100% (Pearson, χ² — 24.681, df = 1; p < 0.001), T/yT3 — 72.3 and 100% (Pearson, χ² — 33.114, df = 1; p < 0.001), T/yT4 — 90.0 and 100% (Pearson, χ² — 4.789, df = 1; p = 0.029) respectively. There are also statistically significant differences when comparing the sensitivity of computed tomography according to the standard protocol and computed tomographic pneumogastrography in determining tumor invasion for all tumor categories: T/yT1 — 0 and 69.4% (Pearson, χ² — 67.880, df = 1; p < 0.001), T/yT2 — 26.1 and 71.1% (Pearson, χ² — 11.666, df = 1; p < 0.001), T/yT3 — 32.9 and 84.6% (Pearson, χ² — 54.900, df = 1; p < 0.001), T/yT4 — 73.3 and 95.7% (Pearson, χ² — 7.916, df = 1; p = 0.005) respectively. In general, the sensitivity of the computed tomography according to the standard protocol for determining the T-stage of gastric cancer was 28.4%, computed tomographic pneumogastrography — 77.1% (Pearson, χ² — 113.505, df = 1; p < 0.001). Computed tomographic pneumogastrography with the possibility of three-dimensional visualization and virtual gastroscopy significantly increases the indicators of the effectiveness of diagnosing gastric cancer — both early forms (category T1) and with deeper invasion (categories T2–T4), demonstrates high sensitivity in determining T/yT-stages.