Clinical manifestations of rectal cancer: change in bowel habits, blood stool, pus and blood stool, or constipation and diarrhea, gradual thinning of stool, obstruction of bowel movement, weight loss and even cachexia in advanced stage Rectal finger examination: it is a necessary examination step to diagnose rectal cancer, about 80% of rectal cancer patients can be found through rectal finger examination, hard and uneven masses can be palpated; in advanced stage, narrowed intestinal cavity masses can be palpated and fixed finger sleeve can be seen with fecal foul and pus blood Rectal microscopy: tumor size and shape can be seen and tissues can be taken directly for pathological examination.