Prognostic factors for cytology-positive gastric cancer: a multicenter retrospective analysis



The prognosis of patients with gastric cancer and positive peritoneal lavage cytology is poor, even after gastrectomy. Though the standard therapy for this population is radical gastrectomy followed by S-1 chemotherapy, treatments vary among institutions and eras. We conducted a multicenter retrospective study to investigate the prognostic factors for cytology-positive gastric cancer.


We reviewed the medical records obtained from 6 institutions, covering 2000–2019. There were 128 patients with positive cytology and no other distant metastases that underwent R1 gastrectomy. Univariate and multivariate analyses to identify prognostic factors for overall survival were conducted using Cox’s proportional hazards models.


The median overall survival time was 18.6 months. In univariate analyses, age (≥ 80 years vs. < 70 years), performance status (2, 3 vs. 0), prognostic nutritional index (< 35 vs. ≥ 40), the extent of lymphadenectomy (D1 vs. ≥ D2), macroscopic type (type 4 vs. non-type 4), and postoperative chemotherapy (none vs. S-1) were significantly correlated with worse survival. Multivariate analysis revealed that lymph node metastasis (pN3b vs. pN0, hazard ratio 4.46, 95% confidence interval 1.17–16.9, p = 0.03) and postoperative chemotherapy (none vs. S-1, hazard ratio 2.28, 95% confidence interval 1.16–4.45, p = 0.02) were independent risk factors for death. No postoperative chemotherapy regimen showed a survival benefit over S-1 monotherapy.


Massive lymph node metastasis was an independent risk factor in cytology-positive gastric cancer. Postoperative chemotherapy was also an independent prognostic factor, though the most beneficial regimen was still uncertain.

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This study was funded by Kawasaki Medical School. This study was conducted at the following 6 institutions; Higashiosaka City Medical Center, Osaka, Japan; Kawasaki Medical School Hospital, Okayama, Japan; National Hospital Organization Osaka National Hospital, Osaka, Japan; Osaka General Medical Center, Osaka, Japan; Yao Municipal Hospital, Osaka, Japan; and Kawasaki Medical School General Medical Center, Okayama, Japan. The authors would like to thank Enago ( for the English language review.

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SE and KN wrote the protocol. SE, KN, MI, KF, JK, and TY gathered data. SE analyzed the data. All authors were involved in the drafting, review, and approval of the manuscript and the decision to submit for publication.

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Correspondence to Shunji Endo.

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Conflict of interest

Dr. Nishikawa reports personal fees from Bristol-Myers Squibb, personal fees from Chugai, personal fees from EA Pharma, personal fees from Eli Lilly, personal fees from Ono, personal fees from Taiho, personal fees from Yakult, outside the submitted work. The other authors report no financial conflicts of interest to disclose.

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Endo, S., Nishikawa, K., Ikenaga, M. et al. Prognostic factors for cytology-positive gastric cancer: a multicenter retrospective analysis. Int J Clin Oncol (2021).

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  • Cell biology
  • Stomach neoplasms
  • Chemotherapy