<prompt> Commonest site of carcinoma colon is:Right side colonLeft side colonTransverse colonCaecum  <response>: Left side colon: Ref: 1177-LB 1181-B L 25thAdenocarcinoma of the colon: - Tumours are more common in the left colon and rectum Microscopically the neoplasm is a columnar cell carcinoma Macroscopically the tumour may take one of four forms Annular, Tubular ulcer, cauliflower Type 4 cauliflower is the least malignant form All carcinoma starts as benign adenoma, the so called adenoma-carcinoma sequence Annular variety gives rise to obstructive symptoms and where as the others more commonly will present with bleeding.Symptoms and signs of colorectal cancerA Right sided tumours: Iron deficiency anemia, abdominal painB Left sided tumours: Rectal bleeding, alteration in bowel habit, tenesmus obstructionC Metastatic disease: Jaundice, ascitis, hepatomegaly, other symptoms and signs from rare sites of metastasis. 