Impact of microscopically positive resection margins (R1) on overall survival and recurrence rate in hepatoblastoma: A systematic review and meta-analysis.

BACKGROUND

The prognostic relevance of microscopically positive (R1) resection margins in hepatoblastoma remains uncertain. While microscopically complete (R0) resection is the gold standard and the primary surgical goal, R1 resections are occasionally accepted to avoid transplantation, partial hepatectomy with vascular replacement in advanced tumors, or re-resection in cases of unexpected positive margins.

METHODS

A systematic review and meta-analysis were conducted according to PRISMA guidelines. Only studies reporting survival outcomes after R1 versus R0 resection in hepatoblastoma were included. Reported hazard ratios (HRs) were extracted; when not available, HRs were reconstructed from published Kaplan-Meier curves using established digitization and reconstruction methods. Pooled estimates of 5-year overall (OS) and event-free survival (EFS) were calculated using random-effects models.

RESULTS

Six included studies, published between 2019 and 2021, comprised 1,418 patients, of whom 197 (13.9 %) had R1 margins. Across both OS and EFS, there was no statistically significant difference in survival between R1 and R0 resections. The pooled 5-year OS and EFS HRs for R1 vs. R0 resections were: OS-pooled HR = 1.12, 95 %-CI 0.78-1.61; EFS-pooled HR = 1.18, 95 %-CI0.83-1.68.

CONCLUSIONS

This meta-analysis suggests that R1 resection margins are not associated with significantly worse OS or EFS compared with R0 resections in hepatoblastoma. However, R0 resection should remain the surgical objective. In selected, e.g. locally advanced cases, minimal margins may be acceptable when vascular replacement or transplantation can be avoided, as current evidence suggests no significant adverse oncologic impact after neoadjuvant chemotherapy. Nevertheless, existing data are limited to retrospective cohorts, underscoring the need for prospective, histopathologically detailed studies.