Relevance: Metachronous peritoneal dissemination (PD) is the most frequent pattern of gastric cancer (GC) progression
 after radical surgery. It is necessary to take into account the existing risk of developing metachronous PD to ensure a substantiated administration of intraperitoneal chemotherapy (ICT) for its timely prevention.
 The purpose of the study was to raise the metachronous PD prognostication efficacy.
 Results: The treatment outcomes of 1,065 radically operated patients (males – 640, 60.1%; females – 425, 39.9%) aged 23 to 89
 years (median age – 63±12) showed that a high risk of GC recurrence in the form of peritoneal dissemination is associated with:
 (1) metastatic invasion of the regional lymph node – pN2-3 – RR 2.0 (95% CI 1.5–2.7), р < 0.001; (2) ulcero-infiltrative and diffuse
 infiltrative forms of primary gastric cancer growth – RR 3.7 (95% CI 2.5–5.5), р < 0,001), and RR 2.3 (95% CI 1.5–3.6), р<0,001;
 (3) serosa invasion by primary GC (pT4) – RR 2.5 (95% CI 1.8–3.6), р<0,001; (4) combined surgical treatment vs. standard surgery –
 RR 1.8 (95% CI 1.2–2.7), р=0.005; and (5) performing gastrectomy vs. distal resection – RR 1.6 (95% CI 1.2–2.2), р=0.004.
 A multivariate analysis (Fine-Grey model) was done to propose a prognostic model for an intraoperative estimate of the
 MPD development probability to determine indications for intraoperative ICT (concordance index – 0.75).
 Conclusion: The proposed nomogram- or formula-based prognostic model allows a differentiated approach to administering intraoperative ICT, taking into account the existing probability of peritoneal dissemination development.