Colorectal cancer is a term that encompasses both colon cancer and rectal cancer. Colon cancer refers to cancer that originates in the longest part of the large intestine, while rectal cancer starts in the last few inches of the large intestine near the anus, according to the National Cancer Institute. Treatment for colorectal cancer is based on the spread and extent of disease, as well as the location of the cancer.
Stage 0, or Carcinoma in Situ
For Stage 0 colon cancer, the small tumor may be removed completely, which is known as a local excision, or a polypectomy may be performed, which is removal of the abnormal polyp. If the tumor is too big, the National Cancer Institute states that resection of part of the colon may be warranted; an anastomosis connects the two healthy parts of the colon once the diseased part is removed. Rectal cancer may be treated with a polypectomy, local excision or a transanal resection.
Stage I
For stage I colon cancer, resection and anastomosis is the standard treatment, according to the National Cancer Institute. Stage I rectal cancers are typically treated by surgery, notes the American Cancer Society. Depending on the extent of the cancer, surgery may be followed by chemotherapy, and radiation therapy may be given. For individuals who are not able to have surgery because they are too ill, radiation therapy is usually given, although the American Cancer Society explains that this is not as effective as surgery.
Stage II
Resection and anastomosis may also be a treatment option for stage II colon cancer. Clinical trials of chemotherapy, radiation therapy or biological therapy after surgery may also be options for some individuals. Stage II rectal cancer is treated by surgery, followed by chemotherapy. The American Cancer Society also mentions that many doctors are recommending chemotherapy and radiation prior to surgery as well, to help shrink the cancer.
Stage III
Stage III colon cancer is typically treated with resection and anastomosis, followed by chemotherapy, according to the National Cancer Institute. Clinical trials of different chemotherapies, radiation therapy or biologic therapy may also be options. Treatment for rectal cancer that is stage III consists of surgery followed by radiation therapy and chemotherapy. Similar to stage II rectal cancers, doctors are frequently administering radiation and chemotherapy to stage III rectal cancer patients prior to surgery as well, in addition to post-surgery treatment.
Stage IV
There are several treatment options for stage IV colon cancer, including resection and anastomosis, surgery on other organs to which the colon cancer has spread, and clinical trials of chemotherapy or biologic therapy. Palliative treatment to relieve any symptoms the cancer may be causing can include radiation therapy and chemotherapy. The National Cancer Institute lists several treatment options for stage IV rectal cancer, including surgery, with or without chemotherapy and radiation before the procedure; palliative treatment with radiation or chemotherapy; placing a stent in the rectum as a palliative measure when the tumor is blocking the rectal opening; and chemotherapy with or without a monoclonal antibody drug.
