Computed tomographic pneumogastrography in determining the types of gastric cancer according to the Lauren classification

Objective . To assess the capabilities of computed tomographic pneumogastrography in determining the types of gastric cancer according to the Lauren classification at the stage of clinical staging. Materials and methods . This study is a single-center retrospective study with 202 patients with gastric cancer included who was treated at the National Medical Research Center of Oncology named after N. N. Petrov from 2015 to 2018. All patients underwent subtotal gastric resection or gastrectomy and computed tomographic pneumogastrography at the stage of clinical staging. For patients undergoing neoadjuvant chemotherapy, CT was performed twice: before chemotherapy and after, immediately before surgery. We studied quantitative and qualitative imaging biomarkers, measured densitometric indices of stomach tumor density in the arterial, portal and delayed phases of scanning at five different points. For patients receiving NACT, all density indices were recorded twice — both before the start of therapeutic treatment, and after, immediately before the surgery. Results . The distribution of gastric cancer types according to Lauren»s classification was as follows: in 59 (29,2 %) intestinal type, 69 (34,2 %) — diffuse, 16 (7,9 %) — mixed, 58 (28,7 %) — indeterminate type. Based on visual characteristics, taking into account the characteristics of tumor growth, 3 main CT-PGG of the gastric cancer type were identified: 1 — tuberous (n = 68, 34,0 %), 2 — intramural (n = 57,3 %) and 3 — mixed (n = 77,4 %). CT-PGG tumor type is associated with Lauren type (χ 2 = 185,19, p <0,001). With a tuberous CT-PGG type, it is possible to assume that the tumor is of an intestinal or indeterminate Lauren type; sensitivity 0,58 (95% CI: 0,49-0,67), specificity 0,1 (95% CI: 0,96-0,1). With an intramural CT-PGG type, the diffuse type of tumor according to Lauren is most likely; sensitivity 0,75 (95% CI: 0,64-0,85), specificity 0,96 (95% CI: 0,91-0,99). With a mixed CT-PGG type, the definition of the type according to Lauren is difficult. In the definition of mixed tumor type according to Lauren, the sensitivity and specificity of mixed CT-PGG tumor type are 0,94 (95% CI: 0,70% -0,1) and 0,67 (95% CI: 0,59-0,73) respectively. Conclusion . The shape of the stomach tumor, determined by CT-PGG, has a high diagnostic efficiency in determining the types of gastric cancer according to Lauren. The tuberous CT-PGG type is typical for tumors of the intestinal type according to Lauren, and the intramural CT-PGG type is typical for tumors of the diffuse type according to Lauren. Tumors of indeterminate Lauren type have any CT-PGG type and contrast pattern. For tumors of a mixed type according to Lauren, a mixed type according to CT-PGG is characteristic, but differential diagnosis with tumors of a tuberous and diffuse type according to Lauren of an atypical form for them is impossible. Tumors of the intestinal and diffuse Lauren type of the CT-PGG type, which is not typical for them, have an atypical contrast pattern.