Comparison of Neoadjuvant Chemotherapy to Surgery Followed by Adjuvant Chemotherapy in Japanese Patients with Peritoneal Lavage Cytology Positive for Gastric Carcinoma

Background: Therapeutic strategies for positive peritoneal lavage cytology [CY(+)] findings have not yet been established. The aim of the present study was to compare the effects of neoadjuvant systemic chemotherapy and surgery followed by S-1 adjuvant chemotherapy for treating gastric carcinoma in patients with CY(+) status without peritoneal metastasis. Patients and Methods: Twenty-three patients with CY(+) status without peritoneal metastasis who underwent curative surgery for gastric carcinoma between October 1999 and December 2014 were included in the study. Ten patients received neoadjuvant systemic chemotherapy followed by surgery, whereas 13 patients underwent surgery, in nine cases followed by S-1 adjuvant chemotherapy. Results: The 5-year survival in both groups was 15%, and no significant difference was observed. However, the prognosis for patients with CY(-) status after neoadjuvant systemic chemotherapy was significantly better than that of patients who were still CY(+) after neoadjuvant systemic chemotherapy (p<0.01). Among all patients, the prognosis of those with less than clinical N2 disease was significantly better than that of patients with clinical N3 (p<0.01). In multivariate analysis, clinical lymph node metastasis was the only independent prognostic factor for CY(+) patients without peritoneal metastasis (p<0.05). Conclusion: The prognosis of gastric carcinoma with CY(+) without peritoneal metastasis is still stage IV disease and is dependent on the degree of clinical lymph node metastasis, in spite of therapeutic treatment.