Table 1 Univariate analysis results show factors associated with pathological lateral lymph node metastasis
Factors | LLN-positive (n = 18) | LLN-negative (n = 49) | Univariate analysis (P value) |
|---|---|---|---|
Patient factors | |||
 Age (years) | 66.5 (47-83) | 65 (33-78) | 0.2529 |
 Gender (male/female) | 9/9 | 29/20 | 0.5024 |
 Preoperative therapy (none/chemotherapy/chemoradiotherapy) | 13/2/3 | 39/6/4 | 0.6262 |
 cT (2/3/4a/4b) | 0/8/2/8 | 3/34/4/8 | 0.0641 |
 Clinically suspected mesorectal LN metastasis (+/−) | 16/2 | 25/24 | 0.0027 |
MRI factors | |||
 MRI-AV (mm) | 34.5 (9-66) | 36 (0.5-95) | 0.4613 |
 Enlarged LLN (positive/negative) a | 16/2 | 9/40 | < 0.0001 |
 MRI-EMVI (positive/negative) | 14/4 | 18/31 | 0.0024 |
 MRF involvement (positive/negative) | 9/7 | 17/29 | 0.1800 |
Surgical factors | |||
 Approach to LLN dissection (laparoscopy/open) | 5/13 | 32/17 | 0.0058 |
 Operation (LAR/sLAR/ISR/APR/TPE) | 1/4/1/10/2 | 7/27/1/13/1 | 0.0500 |
Pathological factors | |||
 Tumor size (mm) | 35 (30–70) | 50 (30–80) | 0.6715 |
 pT (≤ 2/≤ 3) | 18/0 | 41/8 | 0.0289 |
 Mesorectal LN metastasis (positive/negative) | 12/6 | 22/27 | 0.1114 |
 v (positive/negative) | 16/2 | 37/12 | 0.2097 |
 ly (positive/negative) | 5/13 | 6/43 | 0.1443 |
 Perineural invasion (positive/negative) | 8/10 | 24/23 | 0.6326 |
 Differentiation (Well or moderate/poor) | 15/3 | 47/2 | 0.1044 |
 CRM (0/1) | 18/0 | 49/0 | – |
Postoperative course | |||
 Recurrence (positive/negative) | 5/13 | 13/36 | 0.9189 |
 Site of overall recurrence (local recurrence/distant recurrence/local and distant recurrence) | 0/4/1 | 2/10/1 | 0.4177 |
 LLN recurrence (yes/no) | 1/4 | 1/12 | 0.4782 |