People with advanced rectal cancer can have back pain if the cancer tissue has metastasized to the spine and other parts of the body. Rectal cancer in advanced stage usually metastasizes through direct infiltration, lymphatic metastasis, hematogenous metastasis, implantation metastasis, etc. Direct infiltration can involve bladder, prostate, seminal vesicle gland, vagina, ureter and other parts of the body, while lymphatic metastasis is usually carried out through the superior rectal artery, abdominal aorta, inferior mesenteric artery, and it can metastasize to inguinal lymph nodes and other parts of the body. Hematogenous metastasis mainly occurs through portal vein, iliac vein, etc., and can be transferred to different parts such as liver, lung, bone and brain, etc. Implantation metastasis usually occurs in upper segment rectal cancer. When rectal cancer is in advanced stage, it can be transferred to the spine, waist and other parts through hematogenous metastasis, then it can cause back pain, and it is suggested that patients should go to the hospital for treatment in time.