Dataset Information

Prevalence of Metastatic Lateral Lymph Nodes in Asian Patients with Lateral Lymph Node Dissection for Rectal Cancer: A Meta-analysis.

ABSTRACT:

Importance

Rectal cancers occupy the eighth position worldwide for new cases and deaths for both men and women. These cancers have a high tendency to form metastases in the mesorectum but also in the lateral lymph nodes. The therapeutic approach for the involved lateral lymph nodes remains controversial.

Objective

We performed a systematic review and meta-analysis to assess the prevalence of metastatic lateral lymph nodes in patients with lateral lymph node dissection (LLND) for rectal cancer, which seems to be a fundamental and necessary criterion to discuss any possible indications for LLND.

Methods

Data sources-study selection-data extraction and synthesis-main outcome and measures. We searched MEDLINE, EMBASE and COCHRANE from November 1, 2018, to November 19, 2018, for studies reporting the presence of metastatic lateral lymph nodes (iliac, obturator and middle sacral nodes) among patients undergoing rectal surgery with LLND. Pooled prevalence values were obtained by random effects models, and the robustness was tested by leave-one-out sensitivity analyses. Heterogeneity was assessed using the Q-test, quantified based on the I2 value and explored by subgroup analyses.

Results

Our final analysis included 31 studies from Asian countries, comprising 7599 patients. The pooled prevalence of metastatic lateral lymph nodes was 17.3% (95% CI: 14.6-20.5). The inter-study variability (heterogeneity) was high (I² = 89%). The pooled prevalence was, however, robust and varied between 16.6% and 17.9% according to leave-one-out sensitivity analysis. The pooled prevalence of metastatic lymph nodes was not significantly different when pooling only studies including patients who received neoadjuvant treatment or those without neoadjuvant treatment (p = 0.44). Meta-regression showed that the pooled prevalence was associated with the sample size of studies (p < 0.05), as the prevalence decreased when the sample size increased.

Conclusion

The pooled prevalence of metastatic lateral lymph nodes was 17.3% among patients who underwent rectal surgery with LLND in Asian countries. Further studies are necessary to determine whether this finding could impact the therapeutic strategy (total mesorectal excision with LLND versus total mesorectal excision with neoadjuvant radiochemotherapy).

SUBMITTER: Christou N

PROVIDER: S-EPMC8026473 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundLateral pelvic lymph node (LPN) metastasis causes increased lateral local recurrence and poor prognosis. We aimed to investigate the prognostic significance and effective range of dissection for the LPN dissection (LPND) in rectal cancer patients with LPN metastasis.Materials and methodsThrough this large, multicenter retrospective cohort study, we evaluated the therapeutic effect of LPND. From January 2012 to December 2019, 387 rectal cancer patients with clinical evidence of LPN metastasis who underwent total mesorectal excision with LPND were included in the study. According to pathological findings, they were divided into negative (n = 296) and positive (n = 91) LPN groups. Primary endpoints were 3-year overall survival (OS), recurrence-free survival (RFS), and local recurrence-free survival (LRFS).ResultsThe OS, RFS, and LRFS in the positive group were significantly worse than those in the negative group; However, LPN metastases were not independent prognostic risk factors for LRFS (hazard ratio [HR]: 2.42; 95% confidence interval [CI], 0.77-7.64; P=0.132). Among patients with pathological LPN metastases, LPN metastases to the common and external iliac arteries were independent prognostic risk factors both for OS (HR: 4.74; 95% CI, 1.74-12.90; P=0.002) and RFS (HR: 2.70; 95% CI, 1.16-6.29; P=0.021). No significant difference was observed in the 3-year OS (72.3% vs. 70.2%, P=0.775) and RFS rates (60.9% vs. 52.6%, P=0.408) between patients with metastases to the obturator or internal iliac arteries and patients at N2b stage.ConclusionsLPND may be effective in controlling local recurrence in patients with LPN metastasis but not systemic metastases. Patients with LPN metastasis limited to the internal iliac and obturator regions achieve a long-term survival benefit from LPND, and their prognoses may be comparable to those at the N2b stage. Further metastasis to the external iliac or common iliac region should be considered systemic disease, and LPND should be avoided.Clinical trial registrationClinicalTrials.gov, identifier NCT04850027.