"The drainage pathways are as follows: (a) upper rectum: through the superior rectal nodes to the inferior mesenteric nodes, (b) lower rectum: from the lower rectum through the middle rectal nodes to the internal iliac nodes, and (c) anal canal: through the mesorectal (also known as inferior rectal) nodes to the inguinal and femoral nodes."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4664281/

Below the dentate line, anal cancer drainage is superficial inguinal. Above the dentate line, superior rectal (then iliac).