Magnetic Resonance Imaging Directed Surgical Decision Making for Lateral Pelvic Lymph Node Dissection in Rectal Cancer After Total Neoadjuvant Therapy (TNT)

Abstract

Objective: Lateral pelvic lymph node (LPLN) metastases are an important cause of preventable local failure in rectal cancer. The aim of this study was to evaluate clinical and oncological outcomes following magnetic resonance imaging (MRI)-directed surgical selection for lateral pelvic lymph node dissection (LPLND) after total neoadjuvant therapy (TNT). Methods: A retrospective consecutive cohort analysis was performed of rectal cancer patients with enlarged LPLN on pretreatment MRI. Patients were categorized as LPLND or non-LPLND. The main outcomes were lateral local recurrence rate, perioperative and oncological outcomes and factors associated with decision making for LPLND. Results: A total of 158 patients with enlarged pretreatment LPLN and treated with TNT were identified. Median follow-up was 20 months (interquartile range 10–32). After multidisciplinary review, 88 patients (56.0%) underwent LPLND. Mean age was 53 (SD±12) years, and 54 (34.2%) were female. Total operative time (509 vs 429 minutes; P=0.003) was greater in the LPLND group, but median blood loss (P=0.70) or rates of major morbidity (19.3% vs 17.0%) did not differ. LPLNs were pathologically positive in 34.1%. The 3-year lateral local recurrence rates (3.4% vs 4.6%; P=0.85) did not differ between groups. Patients with LPLNs demonstrating pretreatment heterogeneity and irregular margin (odds ratio, 3.82; 95% confidence interval: 1.65–8.82) or with short-axis ≥5 mm post-TNT (odds ratio 2.69; 95% confidence interval: 1.19–6.08) were more likely to undergo LPLND. Conclusions: For rectal cancer patients with evidence of LPLN metastasis, the appropriate selection of patients for LPLND can be facilitated by a multidisciplinary MRI-directed approach with no significant difference in perioperative or oncologic outcomes.

Preoperative lateral lymph node features and impact on local recurrence after neoadjuvant chemoradiotherapy and total mesorectal excision for locally advanced rectal cancer: results from a multicentre international cohort study

“…Three-year LLR rates were respectively 3.4% and 4.6% and did not differ between the two groups (p = 0.85). Three-year LR rates were 12.2% for the LLND group and 9.6% for the non-LLND group (p = 0.44) [24].…”

Neoadjuvant S‐1 and oxaliplatin plus bevacizumab therapy for high‐risk locally advanced rectal cancer: A prospective multicenter phase II study

“…31 Currently, selective LLND after TNT for patients with cLLN+ on MRI is considered a promising strategy that maximizes safety and efficacy, with lateral local recurrence reported to be as low as 3%-4%. 32 On the other hand, the local recurrence rate of selective LLND after RT for patients with cLLN+ in Japan and Korea was reported to be 3%-5%, and the pathologic LLN+ rate was 24%-51%. [33][34][35] The pathologic LLN+ rate after NAC for cLLN+ cases in this study was 22%, but the local recurrence rate was as high as 41% even if extended surgeries were performed.…”

“…On the other hand, the completion rate of short‐term RT is almost 100%, and a total neoadjuvant therapy (TNT) strategy combining RT with NAC is expected, as its oncological benefit has recently been demonstrated 31 . Currently, selective LLND after TNT for patients with cLLN+ on MRI is considered a promising strategy that maximizes safety and efficacy, with lateral local recurrence reported to be as low as 3%–4% 32 . On the other hand, the local recurrence rate of selective LLND after RT for patients with cLLN+ in Japan and Korea was reported to be 3%–5%, and the pathologic LLN+ rate was 24%–51% 33–35 .…”

Risk factors for lateral lymph node metastasis based on the molecular profiling of rectal cancer

“…Recently, the worldwide spread of safe surgical techniques of LLND and the problem of local control, which could not be addressed by preoperative CRT alone, have increased the interest in LLND, even in western countries [38][39][40]. Thus, in both Japan and western countries, it has become established that LLND should be performed selectively in patients, especially those with LLNM, who could truly benefit from the effectiveness of LLND [41].…”