Risk factors and prognostic significance of lateral pelvic lymph node dissection after neoadjuvant chemoradiotherapy for rectal patients with clinically suspected lateral lymph node metastasis

Sicheng Zhou,Zhixiang Zhou,Jianwei Liang,Wei Pei,Yujuan Jiang

doi:10.1186/s12893-021-01443-5

Abstract

AimIt is still controversial whether the addition of lateral pelvic lymph node (LPN) dissection (LPND) to total mesorectal excision (TME) can provide a survival benefit after neoadjuvant chemoradiotherapy (nCRT) in rectal cancer patients with pathological lateral lymph node metastasis (LPNM).MethodsPatients with clinically suspected LPNM who underwent nCRT followed by TME + LPND were systematically reviewed and divided into the positive LPN group (n = 15) and the negative LPN group (n = 58). Baseline characteristics, clinicopathological data and survival outcomes were collected and analysed.ResultsOf the 73 patients undergoing TME + LPND after nCRT, the pathological LPNM rate was 20.5% (15/73). Multivariate analysis showed that a post-nCRT LPN short diameter ≥ 7 mm (OR 49.65; 95% CI 3.98–619.1; P = 0.002) and lymphatic invasion (OR 9.23; 95% CI 1.28–66.35; P = 0.027) were independent risk factors for pathological LPNM. The overall recurrence rate of patients with LPNM was significantly higher than that of patients without LPNM (60.0% vs 27.6%, P = 0.018). Multivariate regression analysis identified that LPNM was an independent risk factor not only for overall survival (OS) (HR 3.82; 95% CI 1.19–12.25; P = 0.024) but also for disease-free survival (DFS) (HR 2.33; 95% CI 1.02–5.14; P = 0.044). Moreover, N1-N2 stage was another independent risk factor for OS (HR 7.41; 95% CI 1.63–33.75; P = 0.010).ConclusionsPost-nCRT LPN short diameter ≥ 7 mm and lymphatic invasion were risk factors for pathological LPNM after nCRT. Furthermore, patients with pathological LPNM still show an elevated overall recurrence rate and poor prognosis after TME + LPND. Strict patient selection and intensive perioperative chemotherapy are crucial factors to ensure the efficacy of LPND.

Highlights

The lateral pelvic lymph node (LPN) is one of the common lymphatic metastasis areas of middle-low rectal cancer, and it has been reported that approximately 10–20% of rectal cancer patients with stage II-III disease develop LPN metastasis (LPNM) outside the field of total mesorectal excision (TME) [1, 2]
Neoadjuvant chemoradiotherapy followed by TME was mostly employed for locally advanced rectal cancer, and several relevant randomized control studies revealed that, compared with TME alone, neoadjuvant chemoradiotherapy (nCRT) followed by TME could reduce the local recurrence rate by approximately 10% in clinical II or III rectal cancer patients [7, 8]
The above significant variables in univariate analysis were included in multivariate analysis, and the results showed that post-nCRT LPN short diameter ≥ 7 mm and lymphatic invasion were identified as independent risk factors for pathological LPNM (Table 3)

Summary

Introduction

The lateral pelvic lymph node (LPN) is one of the common lymphatic metastasis areas of middle-low rectal cancer, and it has been reported that approximately 10–20% of rectal cancer patients with stage II-III disease develop LPN metastasis (LPNM) outside the field of total mesorectal excision (TME) [1, 2]. Neoadjuvant chemoradiotherapy (nCRT) followed by TME was mostly employed for locally advanced rectal cancer, and several relevant randomized control studies revealed that, compared with TME alone, nCRT followed by TME could reduce the local recurrence rate by approximately 10% in clinical II or III rectal cancer patients [7, 8]. Most of the patients in the above study had no LPNM, and the current opinion suggests that nCRT + TME without LPND is not sufficient for patients with enlarged LPN, with a lateral pelvic recurrence rate of 19.5% in patients with a LPN diameter greater than 7 mm [9,10,11,12]

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