Purpose

We aimed to evaluate the surgicopathological outcomes of lateral pelvic lymph node dissection (LPLD) and long-term oncological outcomes of selective LPLD after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer and compare them to those of total mesorectal excision (TME) alone based on pretreatment magnetic resonance imaging (MRI).

Methods

We compared the TME-alone group (2001–2009, n= 102) with the TME with LPLD group (2011–2016, n= 69), both groups having lateral lymph nodes (LLNs) of≥ 5 mm in short axis diameter. The surgicopathological outcomes were analyzed retrospectively. Oncological outcomes were analyzed using the Kaplan-Meier method.

Results

The rates of overall postoperative 30-day morbidity (42.0% vs. 26.5%, P= 0.095) and urinary retention (13.7% vs. 10.1%, P= 0.484) were not significantly different between the LPLD and TME-alone groups, respectively. Pathologically proven LLN metastasis was identified in 24 (34.8%) LPLD cases after nCRT. The LPLD group showed a lower 5-year local recurrence (LR) rate (27.9% vs. 4.6%, P< 0.001) and better recurrence-free survival (RFS)(59.6% vs. 78.2%, P= 0.008) than those of the TME-alone group, while the 5-year overall survival was not significantly different between the 2 groups (76.2% vs. 86.5%, P= 0.094).

Conclusion

This study suggests that LPLD is a safe and feasible procedure. The oncological outcomes suggest that selective LPLD improves LR and RFS in patients with clinically suspicious LLNs on pretreatment MRI. Considering that lateral nodal disease is not common, a multicenter large-scale study is necessary.