TREATMENT

Surgery is the most common initial treatment for colorectal cancer. During surgery, the tumor, a small margin of the surrounding healthy intestine, and adjacent lymph nodes are removed. The surgeon then reconnects the healthy sections of the bowel. In patients with rectal cancer, the rectum sometimes is permanently removed if the cancer arises too low in the rectum. The surgeon then creates an opening (colostomy) on the abdominal wall through which solid waste from the colon is excreted. Specially trained nurses (enterostomal therapists) can help patients adjust to colostomies, and most patients with colostomies return to a normal lifestyle.

When a colorectal cancer is diagnosed, additional tests are performed to determine the extent of the disease. This process is called staging. Staging determines how advanced a colorectal cancer has become. The staging for colorectal cancer ranges from stage I, the least advanced cancer, to stage IV, the most advanced cancer. Stage I colorectal cancers involve only the innermost layers of the colon or rectum. The likelihood of cure (excellent prognosis) for stage I colorectal cancer is over 90%. Stage II cancers exhibit greater growth and extension of tumor through the wall of the colon or rectum into adjacent structures. Stage III colorectal cancers manifest spread of the cancer to local lymph nodes. Stage IV colorectal cancers have metastasized to distant organs or lymph nodes far from the original tumor. For more precise staging information, see colon cancer staging at www.cancer.gov.

With each subsequent stage of colon cancer, the risk for recurrent cancer and death rises. As noted, earlier cancers have lower risks of recurrence and death. By the time an individual has stage IV colorectal cancer, the prognosis is poor. However, even in stage IV colorectal cancer (depending on where the cancer has spread) the opportunity for cure exists.

For early colon cancers, the recommended treatment is surgical removal. For most people with early stage colon cancer (stage I and most stage II), surgery alone is the only treatment required. However, once a colon cancer has spread to local lymph nodes (Stage III), the risk of the cancer returning remains high even if all visible evidence of the cancer has been removed by the surgeon. This is due to an increased likelihood that tiny cancer cells may have escaped prior to surgery and are too small to detect at that time by blood tests, scans or even direct examination. Their presence is deduced from higher risk of recurrence of the colon cancer at a later date ( relapse). Medical cancer doctors (medical oncologists) recommend additional treatments with chemotherapy in this setting to lower the risk of the cancer's return. Drugs used for chemotherapy enter the bloodstream and attack any colon cancer cells that were shed into the blood or lymphatic systems prior to the operation, attempting to kill them before they set up shop in other organs. This strategy, called adjuvant chemotherapy, has been proven to lower the risk of cancer recurrence and is recommended for all patients with stage III colon cancer who are healthy enough to undergo it, as well as for the occasional higher risk stage II patient whose tumor may have been found to have obstructed or perforated the bowel wall prior to surgery.

There are several different options for adjuvant chemotherapy for the treatment of colon cancer. The treatments involve a combination of chemotherapy drugs given orally or into the veins. The treatments typically are given for a total of 6 months. It is important to meet with an oncologist who can explain adjuvant chemotherapy options as well as side effects to watch out for so that the right choice can be made for a patient as an individual.

Chemotherapy usually is given in a doctor's office, in the hospital as an outpatient, or at home. Chemotherapy usually is given in cycles of treatment followed by recovery periods without treatment. Side effects of chemotherapy vary from person to person and also depend on the agents given. Modern chemotherapy agents are usually well tolerated, and side effects for most people are manageable. In general, anticancer medications destroy cells that are rapidly growing and dividing. Therefore, normal red blood cells, platelets, and white blood cells that also are growing rapidly can be affected by chemotherapy. As a result, common side effects include anemia, loss of energy, and a low resistance to infections. Cells in the hair roots and intestines also divide rapidly. Therefore, chemotherapy can cause haiir loss, mouth sores, nausea, vomitting, and diarrhea, but these effects are transient.

Treatment of stage IV colorectal cancer.

Once colorectal cancer has spread distant from the primary tumor site, it is described as stage IV disease. These distant tumor deposits, shed from the primary tumor, have traveled through the blood or lymphatic system, forming new tumors in other organs. At that point, colorectal cancer is no longer a local problem but is instead a systemic problem with cancer cells likely present throughout the body. As a result, in most cases the best treatment is chemotherapy, which is a systemic therapy. Chemotherapy in metastatic colorectal cancer has been proven to extend life and improve the quality of life. If managed well, the side effects of chemotherapy are typically far less than the side effects of uncontrolled cancer. Chemotherapy alone cannot cure metastatic colon cancer, but it can more than double life expectancy and allow for good quality of life during the time of treatment.

Chemotherapy options for colorectal cancer treatment vary depending on other health issues that an individual faces. For fitter individuals, combinations of several chemotherapeutic drugs usually are recommended whereas for sicker people, simpler treatments may be best. Different multidrug combinations combine agents with proven activity in colorectal cancer such as oxaliplatin, 5-FU, irinotecan, cetuximab, panitumumab, and bevacizumab. Regimens often have acronyms to simplify their nomenclature (FOLFOX, FOLFIRI, FLOX). Oxaliplatin, irinotecan, and 5-FU are conventional chemotherapy drugs designed to block cell division non-selectively and typically have greater side effects. Bevacizumab, cetuximab, and panitumumab are newer treatments that target specific aspects of the cancer cell which may be more important to the tumor than the surrounding tissues, offering potentially effective treatments with fewer side effects than traditional chemotherapy. These newer chemotherapeutic agents most often are combined with standard chemotherapy to enhance their effectiveness.

If the first treatment is not effective, second- and third-line options are available that can confer benefit to people living with colorectal cancer. We now know that individuals who receive several different treatments survive longer than those who receive one or two types of treatment. Oncologists and researchers continue to work hard investigating new and better treatment options. New agents are becoming available with the potential to extend life even further. An agent called regorafenib has been approved by the Food and Drug Administration (FDA). Regorafenib has been shown to extend progression-free survival in some people with colorectal cancer who no longer are responding to other existing treatments.

Radiation theraphy in colorectal cancer has been limited to treating cancer of the rectum. As noted earlier, whereas parts of the colon move freely within the abdominal cavity, the rectum is fixed in place within the pelvis. It is in intimate relationship to many other structures and the pelvis is a more confined space. For these reasons, a tumor in the rectum often is harder to remove surgically because the space is smaller and other structures can be involved with cancer. As a result, for all but the earliest rectal cancers, initial chemotherapy and radiation treatments (a local treatment to a defined area) are recommended to try and shrink the cancer, allowing for easier removal and lowering the risk of the cancer returning locally. Radiation therapy is typically given under the guidance of a radiation specialist called a radiation oncologist. Initially, individuals undergo a planning session, a complicated visit as the doctors and technicians determine exactly where to give the radiation and which structures to avoid. Once the plan is formalized, radiation treatments for rectal cancer are typically (in the United States) delivered in daily treatments called "fractions" administered Monday through Friday for about 5 to 6 weeks. Treatment times are short but require many visits. Chemotherapy usually is administered daily while the radiation is delivered. Standard chemotherapy is 5-FU by injection into the vein or as a slow infusion or capecitabine, and an oral form of 5-FU is taken twice daily on the days of radiation. Side effects of radiation treatment include fatigue, temporary or permanent pelvic hair loss, and skin irritation in the treated areas