The role of staging laparoscopy in type 4 gastric cancer.
35 Background: In type 4 gastric cancer, the incidence of peritoneal metastasis which was unexpectedly found during surgery was as high as 40 percent. It is very difficult to detect peritoneal metastasis in clinical imaging such as computed tomography or ultrasound before operation. Staging laparoscopy (SL) is considered to be an only minimal invasive procedure to detect peritoneal metastasis. However, the significance of SL had not yet been fully elucidated. The aim of this study is to assess the role of SL in type 4 gastric cancer. Methods: From September 2002 to March 2012, a total of 169 patients with type 4 gastric cancer who were diagnosed as not having distant metastasis in clinical imaging were enrolled in this study. SL was performed for 56 patients, and the other 113 patients underwent open laparotomy (OL) without SL. We retrospectively examined the incidence of peritoneal metastasis and positive peritoneal cytology and treatment courses in patients who underwent SL and OL. Results: In 56 patients undergoing SL, 23 (41%) had peritoneal metastasis and 40 (71%) had positive peritoneal cytology. Similarly, 54 (48%) had peritoneal metastasis and 86 (76%) had positive peritoneal cytology in 113 patients undergoing OL. There were no significant differences of the incidence of peritoneal metastasis and positive peritoneal cytology between the two groups. Subsequent treatments after SL or OL were diverse depends on patients condition and participating clinical trials, however, 17 (32%) in SL group and 13 (12%) in OL group were treated without surgical interventions. There was no morbidity and mortality in both SL group and OL group. In SL group, open surgery was performed soon afterword in 39 patients. Among them, 2 patients was failed to detect peritoneal metastasis by SL. Therefore the accuracy of detecting peritoneal metastasis in SL was 23/25 (92%). Conclusions: In type 4 gastric cancer, the incidence of peritoneal metastasis was around 40% and positive peritoneal lavage cytology was around 70% in both SL and OL. As SL is less invasive than OL, SL appears to be a useful way to detect peritoneal seeding and establish treatment strategy in patients with type 4 gastric cancer.