Сomparing the incomparable: methodological problems in surgical treatment strategies for rectal cancer with synchronous liver metastases (review)

Vollständiger Abstract

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AIM: to systematically analyze key methodological challenges encountered when comparing surgical strategies for patients with rectal cancer (RC) and isolated synchronous resectable liver metastases. P ATIENT S AND METHODS: a literature search was performed in PubMed/MEDLINE, Cochrane Library, Web of Science, Scopus, and Elibrary (2000–2026). Studies comparing two or more surgical strategies (simultaneous, rectum-first, liver-first) for RC with synchronous liver metastases, methodological articles, RCTs, prospective and retrospective cohort studies, meta-analyses were included. Studies on colon cancer without separate analysis, metachronous or unresectable metastases, and case series with n < 10 were excluded. RESULT S: major methodological limitations were identified: selection bias (patients with different disease burden allocated to different strategies); immortal time bias in staged approaches; asymmetric comparison of complications (one surgery vs. two surgeries); heterogeneity of systemic and radiation therapy regimens; incomplete treatment (up to 35% in liver-first); mixing of colon and rectal cancer populations; limitations of propensity score methods; lack of large RCTs. Proposed solutions include pragmatic and registry-based RCTs, target trial emulation (TTE), stratification by liver resection volume, neoadjuvant therapy regimen, molecular profile, and adherence to reporting guidelines (STROBE, TARGET). CONCLUSION: existing methodological problems substantially limit data interpretation. Definitive conclusions