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Exploratory analysis of lateral pelvic sentinel lymph node status for optimal management of laparoscopic lateral lymph node dissection in advanced lower rectal cancer without suspected lateral lymph node metastasis.

ABSTRACT:

Background

Total mesorectal excision (TME) and lateral lymph node dissection (LLND) without radiotherapy (RT) are standard treatment for lower cT3/4 rectal cancers in Eastern countries. In comparative studies, both TME + LLND and RT + TME yield good local control. Although Japanese guidelines recommend LLND for locally advanced rectal cancers below the peritoneal reflection, LLND dissection of clinically negative lateral pelvic lymph nodes (LPLN) is controversial, and laparoscopic TME + LLND is technically challenging and time-consuming. New optical instruments for laparoscopy allow easy perioperative sentinel lymph node (SLN) identification using ICG. The SLN concept may facilitate accurate diagnosis of LPLN involvement, and thus reduce LLND in laparoscopic rectal cancer surgery. Here we investigated lateral pelvic SLN navigation surgery for SLN detection during laparoscopic rectal cancer surgery.

Methods

This study included 21 patients with clinical StageII/III lower rectal cancer without LPLN enlargement, who underwent curative laparoscopic surgery. All patients underwent TME, followed by lateral SLN identification and biopsy using ICG, and then laparoscopic LLND. ICG fluorescence imaging was conducted using the laparoscopic near-infrared camera system.

Results

Lateral SLNs were successfully identified in 16 (76.2%) of the 21 patients. Among the 15 patients without SLN tumor metastasis, the dissected lateral non-SLNs were all negative.

Conclusions

A lack of metastasis in the lateral pelvic SLN seems to reflect a lack of metastases to all lateral LNs. Our present results suggest that this laparoscopic ICG-guided SLN strategy may be a low-risk and time-saving method to prevent laparoscopic LLND in cases with negative lateral pelvic lymph nodes.

SUBMITTER: Yasui M

PROVIDER: S-EPMC8356457 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ImportanceRectal 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.ObjectiveWe 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.MethodsData 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.ResultsOur 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.ConclusionThe 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).