Krukenberg tumours: which patients should be considered for surgery?-a narrative literature review.

Background and objective: Krukenberg tumours (KTs) are metastatic signet ring cell (SRC) adenocarcinomas of the ovary, arising from the stomach in most cases (70%). Other common primary sites are the colon, appendix and breast. The use of the term "Krukenberg tumour" is inconsistent in the literature which makes data interpretation difficult. Prognosis of KTs is dismal and, in the absence of randomised controlled trials, the best treatment strategies remain controversial. Evidence from retrospective studies suggests that metastectomy is associated with improved survival. Our narrative literature review set out to determine which patients gain maximal survival benefit from surgical management.

Methods: A comprehensive literature search was performed using PubMed and Google Scholar databases, from 1 January 2000 to 15 July 2024, with the terms 'Krukenberg', 'metastatic mucinous adenocarcinoma of ovary'. This search identified 20 full-text manuscripts, including data on 1,815 patients.

Key content and findings: We found that the overall prognosis of these patients remains poor, with a median overall survival (mOS) ranging between 9 and 50 months. Metastectomy is associated with survival benefit only when all visible disease is removed (R0): mOS in patients with microscopic residual disease (R1) or gross residual disease (R2) is similar to mOS in unresected patients (11 vs. 10 months). The following other factors have been identified as independent prognostic factors for survival in multivariate analyses: heated intraperitoneal chemotherapy (HIPEC), adjuvant chemotherapy, curative surgery for the primary tumour, i.e., gastrectomy, no ascites, non-gastric origin, a good performance status, less extensive metastatic disease, i.e., no extra-ovarian disease or no extra-pelvic disease, no peritoneal carcinomatosis or a low Peritoneal Cancer Index (PCI), smaller size of lesion, no SRC features, expression of oestrogen receptor-β (ER-β) and progesterone receptors (PR), metachronous tumours, linitis plastica, tumour grade.

Conclusions: Multiple retrospective analyses have demonstrated that metastectomy is associated with a survival benefit in patients with metastatic mucinous ovarian adenocarcinomas. However, patients with poor prognostic factors are less likely to benefit from surgery and should be counselled accordingly. Diagnostic laparoscopy could be considered before debulking surgery, to assess resectability of disease and to avoid a futile exploratory laparotomy. HIPEC after cytoreductive surgery (CRS) remains controversial, with possible survival benefit for KTs of gastric origin, particularly when peritoneal dissemination is present but the PCI is low.