Importance of Lateral Rectal Lymph node in Low Rectal Cancer

1. A case of Lateral Rectal LNs failure, 2. Concept of Lateral Lymph node involvement

Reference 1: Key Factor

• Sammour T, Chang GJ.  Lateral pelvic lymph node dissection and radiation treatment for rectal cancer: Mutually exclusive or mutually beneficial?Ann Gastroenterol Surg. 2018;00:1–3. https://doi.org/10.1002/ags3.12197 .  
• LRLN in case of low or mid RC should be considered as a part of regional disease and to be mutually addressed during nCRT & Sx. 

1. Low risk of LPLN disease (cT1/T2/early T3) (and Ra*) with cN0-LPLN on MRI: Treatment by TME. 
2. Moderate risk of LPLN disease (cT3/4 with cN0-LPLN on MRI <7mm) (or Rb**): treatment by nCRT + TME +/- LPLND. 
3. High risk of LPLN disease (cN1-LPLN on MRI  >7mm) (Ra or Rb): treatment by nCRT + TME + LPLND. 

• *Ra- above peritoneal reflection **Rb-below peritoneal reflection. 

Reference 2: Key Factors-

• Ogura A et al. Neoadjuvant (Chemo)radiotherapy With Total Mesorectal Excision Only Is Not Sufficient to Prevent Lateral Local Recurrence in Enlarged Nodes: Results of the Multicenter Lateral Node Study of Patients With Low cT3/4 Rectal Cancer. Lateral Node Study Consortium. J Clin Oncol. 2018 Nov 7; 
• https://doi.org/10.1200/JCO.18.00032;  http://www.ascopost.com/News/59493
• Study duration- Jan 2009-Dec 2013, Cases included- cT3/4 rectal cancer up to 8 cm from anal verge who underwent nCRT or RT f/b TME. 
• Total 1216 patients /  703 patients (58%) had visible LNs in baseline MRI / 108 patients developed local recurrence (5yr rate = 10%) and 59 had lateral local recurrence (5 year lateral local recurrence rate = 5.5%).
• 192 patients (16%) have lateral lymph nodes ≥ 7 mm, those undergoing TME and LLND had a 5-year lateral local recurrence rate of 5.7% vs a 5-year rate of 19.5% among those not undergoing LLND.