The Negative Impact of a Non-Therapeutic Laparotomy in Patients With Inoperable Colorectal Peritoneal Metastases.

BACKGROUND: The peritoneum is the third most prevalent location for metastases of colorectal cancer. In patients with resectable disease, cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is the preferred treatment in the Netherlands, achieving median overall survival (OS) of 36-42 months. However, during explorative laparotomy, CRS-HIPEC may appear unfeasible. Evidence on how such non-therapeutic laparotomies affect prognosis is limited. METHODS: This retrospective cohort study included all non-therapeutic laparotomies performed between 01 and 01-2010 and 01-01-2022 in two Dutch tertiary HIPEC-centers. Patient, tumor and treatment characteristics, postoperative morbidity, and survival outcomes were analyzed and compared to existing literature. RESULTS: In total, 108 patients underwent a non-therapeutic laparotomy (discontinued CRS-HIPEC). The main reason was that peritoneal disease was too extensive (56%). Severe postoperative complications (Clavien-Dindo ≥ 3) occurred in 9%. Following a non-therapeutic procedure, 55% of patients received tumor-directed palliative treatment. Median OS of the entire cohort was 6.5 months (95% CI 5.1-8.0). Palliative systemic therapy was the only factor significantly associated with improved OS (12.6 vs. 2.9 months, p < 0.001). CONCLUSIONS: Non-therapeutic laparotomies are associated with decreased survival in patients with extensive peritoneal metastases. Reducing their occurrence is essential. Advances in diagnostic modalities, including MRI, FAPI-PET, artificial intelligence, and developments in bidirectional treatments, may improve preoperative selection and offer alternative therapeutic options. Further research is required.