Impact of preoperative chemotherapy as initial treatment for advanced gastric cancer with peritoneal metastasis limited to positive peritoneal lavage cytology (CY1) or localized peritoneal metastasis (P1a): a multi-institutional retrospective study

Abstract

Background Gastric cancer (GC) patients with peritoneal metastasis are defined as stage IV in the Japanese classification of GC. For patients with peritoneal metastasis limited to positive peritoneal lavage cytology (CY1) and/or localized peritoneal metastasis (P1a), gastrectomy followed by S1 monotherapy is one of the most widely accepted therapeutic strategy in Japan. This study investigated the efficacy of preoperative chemotherapy as initial treatment in GC patients with CY1 and/or P1a. Methods We retrospectively reviewed GC patients diagnosed with CY1 and/or P1a at 34 institutions in Japan between 2008 and 2012. Selection criteria were: adenocarcinoma, no distant metastasis except CY1 or P1a, and no prior treatment. The subjects were divided into an Initial-Chemotherapy group and an Initial-Surgery group, according to the initial treatment. Results A total of 824 patients were collected and 713 eligible patients were identified for this study. As the initial treatment, 150 patients received chemotherapy (Initial-Cx), and 563 patients underwent surgery (Initial-Sx). Initial-Cx regimens were cisplatin plus S1/docetaxel plus cisplatin plus S1/others (n = 90/37/23). Both overall survival (OS) and progressionfree survival (PFS) were similar between the Initial-Cx and Initial-Sx groups (median OS 24.8 and 24.0 months, HR 1.07, 95% CI 0.87-1.3; median PFS 14.9 and 13.9 months, HR 1.04, 95% CI 0.85-1.27). The 5-year OS rates were 22.3% in the Initial-Cx group and 21.5% in the Initial-Sx group. Conclusions Although, the preoperative chemotherapy did not show a survival benefit for GC patients with CY1 and/or P1a, initial-Cx showed favorable survival in patients who converted to P0 and CY0.

Gastrectomy with or without neoadjuvant S-1 plus cisplatin for type 4 or large type 3 gastric cancer (JCOG0501): an open-label, phase 3, randomized controlled trial

“…However, this may not be true in patients with type 4 or large type 3 GC. Furthermore, it has been reported that conversion to negative peritoneal cytology did not result in improved survival in GC [14]. This result also supports the negative association between histological response and survival in the present study.…”

Role of Peritoneal Mesothelial Cells in the Progression of Peritoneal Metastases

“…Li et al [ 102 ] studied 51 gastric cancer patients with preoperative laparoscopic exploration, and reported that 13.7% (7/51) of patients with stage cT3 cancer and below developed CY1 gastric cancer. Other gastric lavage studies have shown similar results [ 103 , 104 , 105 , 106 , 107 ].…”

Predictive Effect of Systemic Immune-Inflammation Index Combined With Prognostic Nutrition Index Score on Efficacy and Prognosis of Neoadjuvant Intraperitoneal and Systemic Paclitaxel Combined With Apatinib Conversion Therapy in Gastric Cancer Patients With Positive Peritoneal Lavage Cytology: A Prospective Study

“…Currently, the prognosis of GC-CY 1 patients is poor, and there is no universal consensus on the most suitable treatment for these patients ( 5 , 8 ). Systemic chemotherapy has been widely accepted as the standard treatment for patients with stage IV and has been proved to improve the prognosis ( 9 ). However, due to the existence of peritoneal-plasma barrier, chemotherapeutic drugs cannot directly act on the abdominal cavity ( 10 ).…”