What's the difference between colon and anal cancer?

Location: Location, type of cell and type of treatments are all different. Anal cancer is located in or around the skin of the anus and is usually squamous cell. Treatment is often chemo and radiation. Colon cancer is actually in the bowel and is an adenocarcinoma. Surgery is usually the first approach. Chemotherapy for colorectal cancers is different than for anal cancer.

The cell type: Colon cancer is primarily an adenocarcinoma anal cancer is primarily a squamous cell type the treatments and work up are completely different. The anus is derived from ectoderm and the colon from endoderm -- allowing for the different cell types. Both colon and anal can have the other type, however much much more rare.

Almost everything: The only thing the same is that colon and anus are part of the GI tract. Otherwise, everything else is different. The type of cells where the cancer originating from are different, the epidemiology is different-hpv is one of the risk factor for anal cancer- while it is not in colon cancer. Therapy is different- chemo/radiation in anal ca. While in colon ca-surgery is possible +/- chemo.