Significance of Intraperitoneal-free KRT20 and CEACAM6 mRNA Expression for Peritoneal Recurrence of Gastric Cancer

BACKGROUND/AIM

Peritoneal lavage cytology is widely used to predict peritoneal recurrence after surgery, but cases of peritoneal recurrence are often recognized in patients with peritoneal lavage cytology negativity (CY0) who underwent no residual tumour (R0) surgery. We used peritoneal lavage fluid before and after gastric cancer surgery to detect cytokeratin 20 (KRT20) and carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) mRNA by RT-PCR.

MATERIALS AND METHODS

We collected peritoneal lavage fluid before and after surgery from 58 patients who underwent gastrectomy. RNA was extracted from these samples and RT-PCR was performed. RNA expression was defined as positive and negative in cases with values higher or lower than the median value. We investigated the relationship between mRNA expression and clinicopathological and surgical factors and prognosis.

RESULTS

Tumour invasion to the sub-serosa (T3) or penetration of the serosa (T4a), lymph node metastasis, and more than 150 ml intraoperative bleeding were significantly correlated with KRT20 mRNA expression. Multivariate analysis of its relationship with peritoneal recurrence showed that the odds ratio of CEACAM6 mRNA for recurrence was high (odds ratio=24.753; 95%CI=0.883-694.06; p=0.0592). All cases with peritoneal recurrence were CEACAM6-positive at pre- or post-surgery. The prognosis of peritoneal recurrence for both KRT20- and CEACAM6-positive cases was significantly poorer than that of other cases. The recurrence-free survival of the CEACAM6-positive group was significantly poorer than that of the CEACAM6-negative group.

CONCLUSION

Measurement of CEACAM6 mRNA in peritoneal lavage fluid at pre- and post-surgery may be useful as a predictor of peritoneal recurrence.

Diagnostic Value of Tumor Markers in Peritoneal Lavage Fluid for Peritoneal Metastasis from Colorectal Cancer

OBJECTIVE

To investigate the diagnostic value of tumor markers in peritoneal lavage fluid in the diagnosis of peritoneal metastasis from colorectal cancer.

METHODS

One hundred eighty-six patients with colorectal cancer and 15 patients with benign disease who underwent surgical treatment were included. The abdominal cavity and pelvis of the patients were lavaged with 200 ml of normal saline immediately after abdominal cavity incision or pneumoperitoneum establishment. Five milliliters of lavage fluid was collected for peritoneal lavage fluid tumor marker detection (pCEA, pCA19-9, pCA125 and pCA724), and another 100 ml of lavage fluid was collected for cytological examination.

RESULTS

There were 13 patients with abdominal and pelvic nodules found intraoperatively and confirmed by postoperative pathology as peritoneal metastasis, and 24 patients were cytologically peritoneal lavage-positive, with a positivity rate of 12.9%. Peritoneal metastasis from colorectal cancer was related to tumor T stage, N stage, and serum CEA and CA19-9 elevation. Peritoneal lavage fluid tumor markers had diagnostic value for patients with and without peritoneal metastasis from colorectal cancer, and the differences were statistically significant (P<0.05). Among them, pCA19-9 had the highest area under the curve (AUC), with 84.62% sensitivity and 85.19% specificity at the cutoff value. pCA19-9 had diagnostic value for peritoneal micrometastasis from colorectal cancer (P<0.05), with an AUC of 0.72.

CONCLUSION

T stage, N stage, and serum CEA and CA19-9 elevation are associated with peritoneal metastasis from colorectal cancer. Peritoneal lavage fluid tumor markers have diagnostic value for peritoneal metastasis from colorectal cancer, among which pCA19-9 has the highest diagnostic value.