Adequate Lymph Node Dissection May Carry a Survival Signal in Intrahepatic Cholangiocarcinoma

Highlights

An updated meta-analysis of 20 studies found no overall survival advantage for lymph node dissection in intrahepatic cholangiocarcinoma when all studies were pooled together.

However, the apparent null effect was strongly influenced by heterogeneity, confounding, and differences in how “adequate” lymphadenectomy was defined across studies.

When bias was reduced with propensity-score matching, lymph node dissection was associated with significantly better survival, and retrieval of at least 6 lymph nodes was linked to a clear survival advantage.

These findings support the idea that the quality and extent of nodal surgery matter more than the binary question of whether lymph nodes were dissected at all.

Background

Intrahepatic cholangiocarcinoma is a biologically aggressive primary liver cancer with a high risk of occult lymphatic spread. Surgical resection remains the only potentially curative treatment, but postoperative recurrence is common and long-term outcomes are often poor. Regional lymph node involvement is one of the strongest prognostic factors, which is why lymph node assessment has important staging value. The more controversial question is whether lymph node dissection itself improves survival, or whether it simply improves staging accuracy without changing the disease course.

That uncertainty has persisted because the available literature is dominated by retrospective series, practice variation, and inconsistent surgical templates. Some centers perform routine regional lymphadenectomy, whereas others omit it selectively or retrieve only a small number of nodes. As a result, prior meta-analyses have repeatedly struggled to isolate a true therapeutic signal from confounding by indication, stage migration, and technical heterogeneity.

The study by Bekheit and colleagues was designed to clarify this issue by updating the evidence base through July 2025 and by asking a more clinically nuanced question: not merely whether lymph node dissection is performed, but whether it is performed adequately.

Study design

This was a systematic review and meta-analysis conducted according to PRISMA principles. The investigators searched multiple databases through July 2025 for studies comparing lymph node dissection versus no lymph node dissection in patients undergoing resection for intrahepatic cholangiocarcinoma. Twenty studies met inclusion criteria.

The primary endpoint was overall survival, summarized using pooled hazard ratios in a random-effects model. The authors also performed prespecified subgroup analyses based on how each study defined adequate lymph node dissection. One subgroup used author-defined thresholds, meaning each study applied its own criterion for adequacy. Another subgroup used a standardized post hoc threshold of retrieval of at least 6 lymph nodes. Meta-regression was used to explore whether propensity-score matching and country of origin influenced the results.

This structure is important because it attempts to separate the effect of the operation itself from the bias introduced by patient selection and variable surgical quality.

Key findings

When all 20 studies were pooled, lymph node dissection did not show a statistically significant overall survival benefit. The pooled hazard ratio was 0.92 with a 95% confidence interval of 0.75 to 1.12, and the P value was .40. In practical terms, that means the aggregate literature does not support a universal survival benefit for lymph node dissection across all settings. But this headline result needs to be interpreted cautiously because heterogeneity was substantial, with an I2 of 86%, indicating that the studies were highly inconsistent with one another.

The meta-regression provided an important clue to that inconsistency. Both propensity-score matching and country of origin significantly modified the observed effect, with a P value of .0002. This suggests that study design and healthcare setting materially shape the apparent benefit of lymph node dissection. Retrospective comparisons without careful adjustment are especially vulnerable to confounding by indication: surgeons may preferentially perform lymphadenectomy in patients who appear fitter, have more favorable disease characteristics, or are treated at centers with more aggressive oncologic practices. Propensity-score matching attempts to balance such differences and therefore offers a more credible estimate of the association.

Indeed, studies using propensity-score matching showed a significant survival benefit associated with lymph node dissection. In that subgroup, the hazard ratio was 0.58, with a 95% confidence interval of 0.44 to 0.77. This is a clinically meaningful effect size and implies that, in better-balanced observational analyses, lymph node dissection may be associated with a roughly 42% relative reduction in the hazard of death.

The most practice-relevant finding came from the analysis of lymph node yield. Using each study’s own definition of an “adequate” dissection produced a trend toward benefit, but it did not reach statistical significance. The pooled hazard ratio was 0.78, with a 95% confidence interval of 0.56 to 1.07 and a P value of .09. This result hints that adequacy matters, but the threshold remained too inconsistent to support a firm conclusion.

When the authors applied a standardized cutoff of at least 6 retrieved lymph nodes, the signal became clearer. Retrieval of ≥6 lymph nodes was associated with significantly better overall survival, with a hazard ratio of 0.76 and a 95% confidence interval of 0.66 to 0.89, P = .02. This finding is especially notable because it transforms the discussion from “yes or no” lymphadenectomy into a quality-based question. A limited nodal sampling procedure may not confer the same oncologic value as a systematic, adequately extensive dissection.

Taken together, the results suggest that the overall literature has been diluted by studies in which lymph node dissection was incomplete, inconsistently defined, or confounded by differences in patient selection and treatment context. Once those problems are reduced, a survival advantage emerges.

Clinical interpretation

The most important takeaway is not that every patient with intrahepatic cholangiocarcinoma automatically benefits from lymph node dissection, but that the benefit appears contingent on surgical adequacy and methodological rigor. This distinction matters because lymph node dissection is not a trivial add-on during hepatectomy. It may increase operative complexity, prolong operative time, and potentially add morbidity in frail patients or those with limited hepatic reserve. Therefore, any therapeutic claim must be supported by a clear signal that the extent and quality of nodal surgery matter.

From a staging perspective, the rationale for nodal evaluation is strong. Accurate nodal staging informs prognosis, adjuvant therapy considerations, and counseling. From a therapeutic perspective, several mechanisms could explain a true survival advantage: removal of occult micrometastatic disease, more complete regional disease clearance, or improved selection of patients for postoperative systemic therapy based on more accurate staging. The current meta-analysis does not prove a biological mechanism, but it strengthens the argument that a sufficiently thorough lymphadenectomy may be more than a diagnostic maneuver.

The finding that propensity-score-matched studies favored dissection also aligns with the broader oncology literature, where unadjusted observational studies frequently under- or overestimate benefits because treatment choice is not random. In this case, the data suggest that less rigorous studies may have obscured the true effect by mixing incomparable patient groups and incomplete procedures.

Strengths and limitations

The study has several strengths. It is up to date, includes a relatively large number of studies for a rare cancer, applies random-effects modeling appropriately, and goes beyond a crude pooled estimate by examining adequacy and confounding. The meta-regression approach is particularly valuable because it identifies sources of between-study variability rather than treating heterogeneity as a nuisance statistic alone.

At the same time, important limitations remain. All included studies were observational, so residual confounding cannot be excluded even in matched analyses. The definition of adequate lymph node dissection still varied, and the ≥6 node threshold, although standardized, was applied post hoc rather than prospectively validated. In addition, country-of-origin effects may reflect differences in surgical practice, pathology processing, case mix, adjuvant therapy access, or registry quality, making causal interpretation difficult. The meta-analysis also cannot determine whether the observed benefit is driven by lymphadenectomy itself, by associated surgical expertise, or by improved stage-directed postoperative management.

Another important caution is that an association with better survival does not automatically justify universal, extensive lymphadenectomy for every patient. The risks and feasibility of nodal dissection must still be individualized, particularly in patients with cirrhosis, borderline liver function, or extensive local disease. A standardized minimum nodal yield is a useful research and quality metric, but it should not be interpreted as a rigid one-size-fits-all mandate without prospective validation.

Implications for practice and research

For clinicians, the study supports a more deliberate approach to nodal evaluation during resection of intrahepatic cholangiocarcinoma. If lymph node dissection is undertaken, it should be systematic and sufficient to yield an informative nodal count. The evidence now suggests that inadequate sampling may fail both goals: it may miss occult disease and it may fail to produce a measurable survival benefit.

For researchers, the next step is standardization. Future prospective studies should define a reproducible lymphadenectomy template, specify a minimum nodal yield, and account for tumor location, liver function, operative strategy, and adjuvant therapy. Ideally, future work should also distinguish between staging benefit and direct therapeutic benefit, since those are not the same outcome. Until then, the current evidence supports a cautious but meaningful conclusion: not all lymph node dissections are equivalent, and adequacy appears to be the key determinant of benefit.

Conclusion

This updated meta-analysis suggests that the absence of a universal survival benefit for lymph node dissection in intrahepatic cholangiocarcinoma is likely explained by heterogeneity and confounding rather than by a true lack of effect. When analyses are adjusted for bias and lymph node retrieval is adequate, a survival advantage emerges. The most compelling benchmark in this study was retrieval of at least 6 lymph nodes, which was associated with improved overall survival. For now, the evidence favors standardized, quality-focused lymphadenectomy rather than indiscriminate or minimal nodal sampling.

Funding and clinicaltrials.gov

Funding details were not specified in the abstract. This was a meta-analysis and did not involve a prospective interventional trial registration; clinicaltrials.gov registration was not reported.

References

Bekheit M, Mroczek TJ, El Boghdady M, Mouindin M, Redfern J, Bucur P. Lymph node dissection in intrahepatic cholangiocarcinoma: Cutting through heterogeneity to reveal the survival signal of an adequate dissection. Surgery. 2026;194:110189. PMID: 41990415.

Bridgewater J, Galle PR, Khan SA, et al. Guidelines for the diagnosis and management of cholangiocarcinoma. Eur J Cancer. 2023;184:1-17.

Rizvi S, Khan SA, Hallemeier CL, Kelley RK, Gores GJ. Cholangiocarcinoma—evolving concepts and therapeutic strategies. Nat Rev Clin Oncol. 2018;15(2):95-111.