Risk factors and therapeutic significance of inguinal lymph node metastasis in advanced lower rectal cancer

Is Elective Inguinal or External Iliac Irradiation During Neoadjuvant (Chemo)radiotherapy Necessary for Locally Advanced Lower Rectal Cancer With Anal Sphincter Invasion?

“…ILN metastases have been interpreted as the consequence of infiltration of the rectal tumors into the anal canal, separated by the dentate line. 15,19 For positive ELNs, most reported cases originated from tumors located closer to the anal verge, although the exact distance and further investigations were not described. 21 The results of this study showed that patients in whom the lower edge of the tumors invaded or located below the dentate line had a higher ILN failure rate, while this phenomenon was not observed in patients with ELN failure.…”

“…13 Furthermore, an advanced primary lesion with proximal lymphatic blockage could cause retrograde nodal spread or ILN and ELN metastases could result from recurrent disease in the pelvis or perineum. 12,14 However, the metastases of ILNs and ELNs from LALRC seem to be relatively rare in clinical practice, with an incidence of approximately 2.9-6.2% for ILNs [15][16][17][18][19][20] and 0.5-7% for ELNs, [21][22][23] respectively. Some risk factors such as dentate line involvement, ILN size, and lymphovascular invasion were reported to be associated with ILN metastases.…”

“…Some risk factors such as dentate line involvement, ILN size, and lymphovascular invasion were reported to be associated with ILN metastases. 19 However, most of the related studies were limited by their relatively small samples, lack of magnetic resonance imaging (MRI), and heterogeneity of perioperative treatment modalities in the early era. 16,17 Besides, the risk factors for ELN metastases have seldomly been explored.…”

Widespread anorectal lymphovascular networks and tissue drainage: analyses from submucosal India ink injection and indocyanine green fluorescence imaging

“…Inguinal lymph node (ILN) metastasis may occur in lower RC. Invasion of the dentate line and lymphovascular invasion are considered risk factors for ILN metastasis [29,30]. However, microanatomical ILN metastatic pathways from the anorectal lesion have not been reported.…”

Fascial Organisation and Lymphatic Systems Around the Pelvic Floor: A Literature Review

“…We believe that these methods can be used to observe functional lymph flow in the anorectal region in detail. A notable region of interest of functional lymphatic flow around the anorectal region is the region from the lower rectum to the inguinal region because tumour invasion of the dentate line and lymphovascular tumour invasion are considered risk factors for inguinal lymph node metastasis (60,61). However, microanatomical inguinal lymph node metastatic pathways have not been reported in anorectal lesions.…”