Diagnostic Accuracy and Clinical Outcomes of the Intraoperative Intelligent Knife (REIMS) in Adult Oncologic Surgery: A Systematic Review.

Rapid intraoperative distinction between malignant and non-malignant tissue may improve resection completeness and reduce reoperation in cancer surgery. The intelligent knife (iKnife) integrates rapid evaporative ionisation mass spectrometry with electrosurgery to provide real-time tissue classification during surgery. This systematic review assessed the diagnostic accuracy and reported clinical outcomes of intraoperative iKnife use in adults undergoing oncological surgery. The review was prospectively registered in PROSPERO (CRD420251049162) and written according to PRISMA 2020 and PRISMA-DTA, given the primary focus on diagnostic test accuracy. PubMed, Embase, Scopus, Web of Science, the Cochrane Library, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform were searched to 10 March 2026. Two reviewers independently screened records, extracted data, and assessed risk of bias and certainty of evidence. Nineteen studies across nine tumour types were included, most of which were small prospective observational or feasibility cohorts. Reported sensitivity ranged from 60% to 100% and specificity from 80.7% to 100%, with high point estimates in ovarian, breast, colorectal and soft-tissue sarcoma settings. Downstream clinical outcome data were limited to margin status in 10 studies, reoperation in 3, complications in 4 and recurrence in 1, with no report of survival. The iKnife shows promise as a real-time intraoperative diagnostic adjunct, but evidence that it improves patient outcomes remains limited. Larger prospective multicentre studies with standardised outcomes and follow-up are required.