Usefulness of circulating tumor DNA (ctDNA) to guide surgical decision-making and predict recurrence in cancer patients undergoing oncological resection: a scoping review

ABSTRACT Introduction: Curative-intent surgical resection is the mainstay of treatment for most localized solid tumors; however, a considerable proportion of patients experience recurrence due to micrometastatic residual disease that is undetectable by imaging or conventional serum markers. Decisions along the surgical pathway (patient selection, timing and extent of surgery, indication for neoadjuvant or adjuvant therapy, and surveillance) are still based on TNM staging and clinicopathological factors with limited accuracy at the individual level. In this context, circulating tumor DNA (ctDNA) has emerged as a minimally invasive biomarker capable of detecting molecular residual disease (MRD), stratifying the risk of recurrence, and anticipating clinical relapse. Objective: To map and synthesize the available scientific evidence on the use of ctDNA to guide surgical decision-making and predict recurrence in adult patients with solid tumors undergoing curative-intent oncological resection. Methods: A scoping review will be conducted following the Joanna Briggs Institute (JBI) methodology and the PRISMA-ScR guideline. The search will be performed in PubMed/MEDLINE, Scopus and Web of Science, including studies published between January 2014 and October 2026 in English, Spanish, and Portuguese. Study selection will be carried out by pairs of independent reviewers using RAYYAN, with discrepancies resolved by a third investigator. Data will be extracted using a Microsoft Excel matrix, and the analysis will be descriptive and thematic, organized by tumor type and clinical decision point. Expected results: A broad but heterogeneous body of evidence is expected, concentrated in colorectal cancer, with variability in detection platforms, sampling time points, positivity criteria, and reported outcomes. Consistent evidence is anticipated on the prognostic value of postoperative ctDNA for predicting recurrence, along with growing evidence from randomized clinical trials on its usefulness in guiding adjuvant therapy, and scarcer evidence on its use for strictly surgical decisions (patient selection, extent of resection, and organ preservation). The findings will serve as a basis for future research and for the implementation of this technology in the Latin American context. Descriptors (MeSH): Circulating Tumor DNA; Liquid Biopsy; Neoplasm, Residual; Neoplasm Recurrence, Local; Surgical Oncology; Clinical Decision-Making Keywords: ctDNA, circulating tumor DNA, liquid biopsy, molecular residual disease, minimal residual disease, oncological resection, surgical oncology, recurrence, ctDNA-guided adjuvant therapy, postoperative surveillance, scoping review.