The main treatment for colorectal cancer is surgery. Precisely which operation is chosen will depend on the site and severity of the tumor: some, or, in severe cases, all, of the colon and rectum may have to be removed. Surgical practice now leans towards techniques that conserve as much bowel as possible, compared to even only a few years ago.
Colostomy is an operation that may be recommended at any age, not just in high risk cases, or the elderly. Pre-operative radiotherapy may, in certain cases, be recommended to reduce the volume of the tumor. This may help the surgeon preserve the rectum and anus, and avoid a colostomy. If the rectum has to be removed, it may be possible for the surgeon to make a pouch using another part of the intestine (an ileal pouch), which will enable the patient to continue to eliminate fecal matter in a relatively natural way.
Chemotherapy also has a crucial role to play in advanced and inoperable disease, though it would rarely be the only treatment recommended. Finally, both pre- and post-operative radiotherapy, depending on the particular case, may also have an important role: such treatment has been shown to reduce local relapses of the disease, and improve overall survival.
Targeted therapies are only currently used if the cancer has spread (metastasized). One such drug, bevacizumab, is a monoclonal antibody which blocks the signaling protein known as VEGF (vascular endothelial growth factor). It may be indicated for the treatment of advanced colorectal cancer, combined with chemotherapy.
Cetuximab and panitumumab are also monoclonal antibody agents which work in a similar way to bevacizumab. They have been approved for use in combination with chemotherapy with irinotecan and oxaliplatin in patients who have an unmutated KRAS gene.