A 78-year-old man has carcinoma of the rectum. The cancer is likely to metastasize the veins into which of the following structures?

Cancer cells from rectal cancer are likely to metastasize to the liver the superior rectal, inferior mesenteric, splenic, and poal veins. Cancer cells are not directly spread to the other organs listed. The spleen and duodenum drain their venous blood to the poal venous system, and the kidney and suprarenal gland empty into the caval (inferior vena cava) system.