Transition to lateral lymph node dissection in rectal cancer: Forty-five years of outcomes data.

Purpose: To determine how outcomes of lateral lymph node dissection for rectal cancer have changed over time.

Methods: This retrospective study included patients with rectal cancer without distant metastasis who underwent total mesorectal excision and lateral lymph node dissection at our institution between 1975 and 2020. We examined the association of surgical time period with relapse-free and overall survival. Multivariable analyses were performed using Cox proportional hazards regression models.

Results: Among a total of 992 patients, 386 underwent surgery in 1975-2000, 296 in 2001-2010, and 310 in 2011-2020. Overall, 924 patients (93%) underwent surgery without preoperative therapy. The respective 5-year relapse-free survival rates were 64.2%, 64.2%, and 68.2% (P = .314), and the 5-year overall survival rates were 72.3%, 84.0%, and 89.3% (P < .001). Overall survival could be stratified by surgical time period, especially stage III (P < .001). In patients with lateral lymph node metastasis, the 5-year overall survival rate was 43.5% in 1975-2000, 61.1% in 2001-2010, and 71.1% in 2011-2020 (P = .003). Multivariable analysis revealed significant differences in overall survival between 2011-2020 and 1975-2000 (hazard ratio, 2.81; P < .001) and between 2011-2020 and 2001-2010 (hazard ratio, 1.59; P = .040), but not in relapse-free survival.

Conclusion: The impact of lateral lymph node dissection on rectal cancer treatment may not have changed in 45 years, given the lack of difference in relapse-free survival. Treatment outcomes after recurrence may have improved. The prognosis remains poor for lateral lymph node metastasis, highlighting the need for further development of multimodality treatments.