Effects of laparoscopic radical gastrectomy on the peritoneal micrometastases of gastric cancer in patients with serosal invasion

Objective:To investigate the effects of laparoscopic radical gastrectomy on the peritoneal micrometastases of gastric cancer in patients with serosal invasion.
Methods:The clinical data of 114 patients with gastric cancer who underwent laparoscopic radical gastrectomy at the Southwest Hospital between October 2012 and October 2014 were retrospectively analyzed. The peritoneal irrigation fluids and tissue specimens from surgical resection were collected, respectively. The area of serosal invasion in the tissue specimens was calculated by AutoCAD software. There were 32 patients without serosal invasion (A group), 30 patients with the area of serosal invasion<5 cm2 (B group) , 27 patients with the area of serosal invasion≥5 cm2  and ≤10 cm2 (C group) and 25 patients with the area of serosal invasion>10 cm2 (D group). The patients of the B, C and D groups were confirmed in the T4a stage of gastric cancer. The relative expressions of carcinoembryonic antigen (CEA) mRNA and dopa decarboxylase (DDC) mRNA in the peritoneal irrigation fluids were detected by the fluorescent quantitative realtime PCR (RTPCR). The followup by outpatient examination and telephone interview were done up to April 2015. The count data were analyzed by the chisquare.  The measurement data with normal distribution were presented as ±s. The comparison among groups was analyzed using the ANOVA. The preoperative and postoperative comparisons were analyzed by the repeated measures ANOVA. The survival curve was drawn by KaplanMeier method, and the survival analysis was done using the Logrank test.
Results:The relative expressions of CEA mRNA in the preoperative peritoneal irrigation fluids in the A, B, C and D groups were 0.172±0.013, 0.194±0.017, 0.221±0.018 and 0.256±0.021, respectively. The relative expressions of CEA mRNA in the postoperative peritoneal irrigation fluids in the A, B, C and D groups were 0.199±0.012, 0.217±0.018, 0.245±0.012 and 0.565±0.026, respectively. The relative expressions of DDC mRNA in the preoperative peritoneal irrigation fluids in the A, B, C and D groups were 0.186±0.011, 0.227±0.021, 0.244±0.019 and 0.268±0.025, respectively. The relative expressions of DDC mRNA in the postoperative peritoneal irrigation fluids in the A, B, C and D groups were 0.213±0.018, 0.257±0.020, 0.281±0.024 and 0.573±0.049, respectively. There were significant differences in the above indexes among the 4 groups (F=291.865, 397.488, 289.541, 381.769, P<0.05). The relative expressions of CEA mRNA and DDC mRNA in the preoperative peritoneal irrigation fluids of the A, B and C groups were compared respectively with those in the postoperative peritoneal irrigation fluids of the A, B and C groups , with no significant differences (F=1.651, 0.681, 1.381, 1.179, 1.309, 1.321, P>0.05). The relative expressions of CEA mRNA and DDC mRNA in the preoperative peritoneal irrigation fluids of the D group were compared respectively with those in the postoperative peritoneal irrigation fluids of the D groups , with significant differences (F=46.228, 7.455, P<0.05). Onehundred and four patients were followed up for a median time of 15.5 months (range, 3.0-30.0 months) with a followup rate of 91.23%(104/114). Among the 104 patients with followup, the 2year cumulative survival rates of the A, B, C and D groups were 90.6%, 83.3%, 77.7% and 64.0%, respectively, showing a significant difference in the survival among the 4 groups (χ²=14.600, P<0.05). The results of comparisons among the A, B and C groups showed no significant differences in the survival (χ²=0.733, 1.045, 0.034, P>0.05).The survival in the D group was compared with those in the A, B and D groups, with significant differences (χ²=9.081, 4.939, 3.957, P<0.05).
ConclusionLaparoscopic radical gastrectomy in patients with the area of serosal invasion≤10 cm2 is safe and feasible, without increasing the rate of peritoneal micrometastases.