[Treatment strategy for patients with CY1 gastric cancer using subgroup analyses].

Background and Aims: Recent advances in anti-cancer drug treatments enable us to improve prognosis in Stage IV gastric cancer. In particular, in recent reports patients with only cytology positive (CY1) non-curative factors have comparatively better prognosis than others. This study was designed to evaluate our outcomes, to allow identification of CY1 gastric cancer patients and to investigate new treatment strategies.
Patients and Methods: Between 2000 and 2008, 336 patients underwent peritoneal washing cytology for gastric cancer intra-operatively. Of these, 35 patients (10.4%) were diagnosed with CY1 gastric cancer.
Results: 1 ) In all CY1 gastric cancers, 1-year, 3-year, and 5-year survival rates were 49%, 11%, and 5.7%, respectively. Clinical factors such as number of non-curative factors (p=0.008) and gastrectomy (p=0.001)were significantly related to poor prognosis. 2 ) The number of CY1 patients with only CY1 non-curative factors (Group C) and multiple non-curative factors (Group CM)were 14 and 21, respectively. The number of CY1 patients with gastrectomy and without gastrectomy were 30 (MST 366 days, Group C: 14 Group CM: 16) and 5 (MST: 88 days, Group CM: 5), respectively. 3 ) In CY1 patients with gastrectomy, patients treated with S-1 based chemotherapy had better prognosis in both Group C and Group CM. 4 ) 8 CY1 patients with neoadjuvant chemotherapy (NAC) followed by gastrectomy (MST 501 days, 1-year survival rate 62.5%) tended to have better prognosis than those without NAC (MST 132 days, 1-year survival rate 25.0% (p= 0.055).
Conclusions: Gastrectomy, number of non-curative factor, S-1 based chemotherapy and NAC were keys to improving prognosis by subgroup analyses in CY1 gastric cancer.