In 2013 it is estimated that 102,480 Americans will be diagnosed with colon cancer. Colorectal cancer is the third most commonly diagnosed cancer in men and women. Of those, 40,340 will be diagnosed with rectal cancer.
Radiation therapy is often used in conjunction with surgery and chemotherapy to treat cancers of the colon, rectum and anus. Treatment involves focused radiation to the bowel and pelvis to treat cancer cells in the area. Surrounding healthy tissue can be affected, but normal cells are often better able to heal from radiation injury, compared to cancer cells, because they have maintained the ability to repair radiation-induced damage.
- For colon cancer, depending on the location and stage of your cancer, radiation can lower the chance of recurrence.
- For some rectal cancers, radiation therapy is given with chemotherapy to make the tumor smaller so it can be removed more easily during surgery. In some cases, radiation can allow an organ-sparing surgery to be possible. It is also common for radiation and chemotherapy to be given before surgery for rectal cancer.
- Anal cancer can often be treated with radiation therapy and chemotherapy, as an organ-preserving approach that avoids the need for surgery.
Surgery often plays a key role in treatment. For colorectal cancers, it is the main curative treatment. The surgeon will determine how much of the large bowel needs to be removed, but often it involves the removal of a section of the colon. Because the tumor can spread to lymph nodes nearby, often some lymph nodes are removed at the time of surgery. Depending upon the location of the tumor, surgery may or may not allow normal bowel function afterwards.
For anal cancers, surgery is less frequently used at the time of diagnosis because effective organ-preserving approaches are available. If bowel function is poor, sometimes surgery is used at first, but often it is reserved as a second chance for cure where organ-preserving treatment does not succeed. Because surgery for the anal canal involves removing the area responsible for how you go to the bathroom, a surgery called a colostomy to re-route bowel movements is usually necessary as well.
While surgery and radiation focus directly on treating the bowel or pelvic area, medication is often recommended to improve cure rates. A medical oncologist will evaluate you and determine what medications may be most helpful.
Chemotherapy is a kind of medication that can destroy cancer cells by different methods. Often, two or more drugs may be combined for the best results. The dose and schedule for treatment varies, as some chemotherapy may be every few weeks and in some cases, it’s given daily. It also differs depending upon whether it’s colon or anal cancer. For more details about these drugs, ask your medical oncologist what may be best for you.