The optimal treatment in patients with gastric cancer and peritoneal disease remains controversial. Some guidelines indicate palliative treatment only, while others consider surgical treatment in case of positive lavage cytology (CY+) or limited peritoneal disease. Here, we analyzed the role of peritoneal disease in patients with gastric cancer, and the prognostic relevance of response to neoadjuvant therapy. In this retrospective cohort analysis, we analyzed patients with adenocarcinoma of the stomach or esophago-gastric junction from a single center operated between 2011 and 2019. According to histology and lavage cytology, patients were classified into four risk groups: (A) no peritoneal disease, (B) CY+ who converted to negative lavage cytology (CY−) after neoadjuvant chemotherapy, (C) CY+ without conversion after chemotherapy, and (D) patients with visible peritoneal metastasis. Overall, n = 172 patients were included. At initial presentation, n = 125 (73%) had no peritoneal disease, and about a third of patients (n = 47, 27%) had microscopic or macroscopic peritoneal disease. Among them, n = 14 (8%) were CY+ without visible peritoneal metastasis, n = 9 converted to CY− after chemotherapy, and in n = 5 no conversion was observed. Median overall survival was not reached in patients who had initially no peritoneal disease and in patients who converted after chemotherapy, resulting in 3-year survival rates of 65% and 53%. In contrast, median overall survival was reduced to 13 months (95% CI 8.7–16.7) in patients without conversion and was 16 months (95% CI 12–20.5) in patients with peritoneal metastasis without difference between the two groups (p = .364). The conversion rate from CY+ to CY− was significantly higher after neoadjuvant treatment with FLOT (5-fluorouracil plus leucovorin, oxaliplatin, and docetaxel) compared to ECF (epirubicin, cisplatin, and 5-fluorouracil) (p = 0.027). Conversion of CY+ to CY− after neoadjuvant chemotherapy with FLOT is a significant prognostic factor for a better overall survival. Surgical treatment in well-selected patients should therefore be considered. However, peritoneal recurrence remains frequent despite conversion, urging for a better local control.

中文翻译：

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腹膜细胞学阳性胃癌：诱导化疗后转为阴性腹膜细胞学的生存获益

胃癌和腹膜疾病患者的最佳治疗方案仍存在争议。一些指南仅指示姑息治疗，而其他指南则考虑在灌洗细胞学阳性 (CY+) 或局限性腹膜疾病的情况下进行手术治疗。在这里，我们分析了腹膜疾病在胃癌患者中的作用，以及对新辅助治疗反应的预后相关性。在这项回顾性队列分析中，我们分析了 2011 年至 2019 年间运营的单个中心的胃或食管-胃结合部腺癌患者。 根据组织学和灌洗细胞学，将患者分为四个风险组：（A）无腹膜疾病, (B) 新辅助化疗后转化为灌洗细胞学阴性 (CY−) 的 CY+，(C) 化疗后未转化的 CY+，(D) 可见腹膜转移的患者。总体而言，包括 n = 172 名患者。在初次就诊时，n = 125 (73%) 没有腹膜疾病，大约三分之一的患者 (n = 47, 27%) 有显微或肉眼可见的腹膜疾病。其中，n=14（8%）为CY+，无可见腹膜转移，n=9在化疗后转化为CY-，n=5未观察到转化。最初没有腹膜疾病的患者和化疗后转行的患者未达到中位总生存期，导致 3 年生存率分别为 65% 和 53%。相比之下，未转化患者的中位总生存期缩短至 13 个月（95% CI 8.7-16.7），而腹膜转移患者的中位总生存期缩短至 16 个月（95% CI 12-20.5），两组之间没有差异（p = . 364）。与 ECF（表柔比星、顺铂和 5-氟尿嘧啶）相比，在用 FLOT（5-氟尿嘧啶加亚叶酸、奥沙利铂和多西他赛）进行新辅助治疗后，从 CY+ 到 CY- 的转化率显着更高（p = 0.027）。FLOT 新辅助化疗后 CY+ 向 CY- 的转化是提高总生存率的重要预后因素。因此，应考虑对精心挑选的患者进行手术治疗。然而，尽管进行了转换，腹膜复发仍然很频繁，迫切需要更好的局部控制。FLOT 新辅助化疗后 CY+ 向 CY- 的转化是提高总生存率的重要预后因素。因此，应考虑对精心挑选的患者进行手术治疗。然而，尽管进行了转换，腹膜复发仍然很频繁，迫切需要更好的局部控制。FLOT 新辅助化疗后 CY+ 向 CY- 的转化是提高总生存率的重要预后因素。因此，应考虑对精心挑选的患者进行手术治疗。然而，尽管进行了转换，腹膜复发仍然很频繁，迫切需要更好的局部控制。