• The Role of Treatment in Colorectal Cancer
• Chemotherapy
• Radiation Therapy
• Treatment Strategies
  Rectal Cancer
  Colon Cancer
  Metastatic Colon Cancer
• Follow-up Care
• Clinical Trials

The Role of Treatment in Colorectal Cancer

Colorectal cancer treatment is based mainly on the size, location, and extent of the tumor, and on the patient's general health. Patients are usually treated by a team of specialist physicians, including a gastroenterologist, surgeon, medical oncologist and radiation oncologist.

Several different types of treatment are often combined to treat colorectal cancer. Surgery to remove the tumor is the cornerstone of treatment for tumors found to be potentially curable. The primary goal of surgery is complete removal of the tumor and nearby lymph nodes. Maintenance or restoration of normal bowel function is a major focus of colorectal cancer surgery as well.

While complete surgical removal of colorectal cancer is the most important step towards achieving a cure, relapses can occur. Additional chemotherapy and, in cases of rectal cancer, chemotherapy and radiation therapy, has been proven to improve a patient's chance for cure and longer life.

A medical oncologist is the doctor who prescribes chemotherapy. Along with oncology nurses and pharmacists, the medical oncologist will also help to prevent or minimize any chemotherapy-associated side effects. Furthermore, your medical oncologist usually is the physician who coordinates treatment provided by other specialists.

Specific chemotherapy regimens depend on whether the patient is being treated for rectal cancer, colon cancer, or metastatic colorectal cancer (cancer that started in the colon or rectum but has spread to other organs).

Chemotherapy

Chemotherapy is the use of anticancer drugs to kill cancer cells. Patients who have had their cancer surgically removed may be given chemotherapy to destroy any cancerous cells that remain in the body. The use of chemotherapy in this situation is called adjuvant chemotherapy. Adjuvant means "additional help," and indeed, adjuvant chemotherapy has been clearly proven to improve a patient's chance for cure from colorectal cancer. In cases in which tumors cannot be surgically removed, chemotherapy may be helpful in controlling tumor growth or relieving tumor related symptoms.

Chemotherapy is a systemic therapy, meaning that the drugs enter the bloodstream and travel through the body. Most anticancer drugs are given by injection directly into a vein (IV) or by means of a catheter, a thin tube that is placed into a large vein and remains there as long as it is needed. Some anticancer drugs are given in the form of a pill.

Chemotherapy Side Effects

Chemotherapy affects normal as well as cancer cells, and side effects result from chemotherapy's impact on normal tissue. The type of side effects that a patient may experience depends largely on the specific drugs and the dose given. Side effects of 5-flourouracil chemotherapy include mouth sores, diarrhea, nausea and vomiting, and fatigue. Fingernails or a narrow strip of skin overlying the veins used to give chemotherapy may darken. Less often but more serious side effects may occur, such as infection or bleeding. Irinotecan, also known as CPT-11 or Camptosar, is another intravenous chemotherapy used either in combination or in sequence with 5-fluorouracil to treat patients with metastatic colorectal cancer. Irinotecan has some side effects in common with 5-fluoruracil such as nausea, vomiting, fatigue, and the remote possibility of bleeding or infection. Diarrhea associated with irinotecan can be severe. Medical oncologists and oncology nurses teach their patients strategies to make all side effects as mild as possible.

Radiation Therapy

Radiation therapy involves the use of high-energy x-rays to kill cancer cells. It is a local therapy, meaning that it affects cancer cells only in the area where the radiation is directed. Radiation is for the most part limited for use in patients with cancer of the rectum. Doctors may use radiation therapy before surgery to shrink a tumor so that it is easier to remove. Alternatively, radiation may be given after surgery to destroy cancer cells that possibly remain. Radiation therapy improves a patient's chance of being cured of rectal cancer, whether it is administered before or after surgery. Radiation therapy is also used to relieve symptoms. Radiation oncologists along with physicists and radiation oncology nurses work to plan your radiation treatment and to prevent or minimize treatment related side effects.

Click here for more information about radiation therapy for colorectal cancer.

Treatment Strategies

Rectal Cancer

TME: A Revolution in Rectal Cancer Treatment

In recent years, cancer surgery has witnessed an increased focus on preserving function and quality of life. The development of total mesorectal excision (TME) and autonomic nerve preservation in
the treatment of rectal cancer offers an excellent example of this philosophy. Since the introduction of TME-based operations two decades ago, patients undergoing the procedure have experienced a much greater survival rate, significantly lower rates of local recurrence, and higher rates of both sphincter preservation and the preservation of sexual and urinary functions than with conventional procedures (see chart below).

The numbers are astounding and represent a truly dramatic turnaround in the treatment of rectal cancer. Two physicians from opposite sides of the Atlantic were instrumental in TME's development: Mr. R.J. Heald, a surgeon in Great Britain and Warren E. Enker, MD, the chief of Surgical Oncology and the associate director of Continuum Cancer Centers of New York, and associate chairman of the Department of Surgery at Beth Israel Medical Center.

The most recent results from a long-term study by Dr. Enker and his colleagues demonstrate the benefits of TME. The study reports 544 rectal cancer patients who have undergone TME from October 1979 through December 1998 with a minimum two-year follow-up. The recent results
found that the cancer-related 5-year survival is 73.5 percent for the 537 of 544 patients with known follow-up, while the 5-year local recurrence rate is 5.2 percent. The national rate of recurrence is 30 percent. "Now you walk out of surgery with a good prognosis, an intact sphincter, intact urinary and sexual functions, a good body image and a good outlook," Dr. Enker explains. "whereas in the past, you suddenly became an old person with a colostomy and a very bad prognosis."

In the past, surgeons treating rectal cancer took out the surrounding tissues, blood vessels and lymph nodes and left the patient impotent and with a colostomy. Eventually, sphincter-preserving operations were perfected, but the operation was still done bluntly without direct vision, and surgeons often left behind cancerous lymph nodes. Then, Dr. Enker discovered effective anatomic ways to remove rectal cancer that do not damage normal function

Noting that the rectum and mesorectum were encased by a thin membrane (the visceral layer of the pelvic fasciae), while the muscles, blood vessels and nerves for sexual function were covered by their own separate layer (the parietal layer), Dr. Enker found that he could dissect between those two planes in a space that permitted the removal of the affected part of the rectum as an intact structure, while leaving intact the autonomic nerves that control sexual and urinary function.

Also, mobilizing the rectum completely allows for the preservation of the unaffected part of the rectum. Dr. Enker and his team also perform the operation under direct vision, using sharp dissection instead of blindly cutting with blunt dissection. Over the last 10 years, the operation has
been widely adopted as the gold standard for rectal cancer. Current studies are being done to see what additional value radiation and chemotherapy have in combination with this operation.

Chemoradiation

"Chemoradiation" refers to the carefully orchestrated simultaneous administration of chemotherapy and radiation treatments. Chemoradiation is an important tool in the treatment of rectal cancer. The term "neoadjuvant" refers to the concept of administering chemotherapy and/or radiation therapy prior to surgery. The purpose of neoadjuvant chemoradiation therapy is twofold: to shrink a tumor to facilitate subsequent surgical removal and to improve a patient's chance for cure. Alternatively, patients with rectal cancer of a size and location that permit resection first should subsequently have adjuvant chemoradiation therapy to improve their chance for a cure.

A typical chemoradiation regimen might consist of daily (Monday through Friday) radiation treatments concurrent with daily (Monday through Friday) continuous infusion 5-fluorouracil (5-FU). This chemoradiation is typically given over a period of five to six weeks. Chemotherapy is given with radiation therapy in order to sensitize tumor cells to radiation, and because the combination has been shown to be more effective than the use of either modality alone. Continuous infusion rather than bolus (a daily 5-10 minute infusion) chemotherapy is preferred as it has resulted in improved survival rates in one study. This regimen may be given pre- or postoperatively for locally advanced tumors (T3/T4 or N1/N2) where it has been shown to reduce the chance of tumor recurrence and improve the chance for cure.

Colon Cancer

Patients with colon cancer that has been surgically removed and is found to involve the nearby lymph-nodes (stage 3 disease) should be offered chemotherapy to improve chances for cure. Some patients whose cancer does not extend into the lymph nodes but has features that predict a higher risk of relapse may also benefit from adjuvant chemotherapy. These high-risk features include tumors that have perforated the bowel wall, tumors that invade blood or lymph vessels of the colon, or tumors that nearly obstruct the colon. Currently, 5-fluorouracil based chemotherapy with leucovorin is the recommended type of adjuvant chemotherapy for all of the above situations. Therapy may be given once a week or for five days in a row, Monday through Friday, and repeated every 28 to 35 days. In either the weekly or daily scheme, therapy should be continued for approximately 6 months.

There are no proven benefits for adjuvant therapy in stage I disease, so none is recommended.

Metastatic Colorectal Cancer

Assessing the location, size, and number of metastases is very important in evaluating patients who present with or eventually develop metastatic colorectal cancer. This information directs treatment decisions with respect to surgical options. Patients whose primary tumor is "resectable" (able to be completely removed surgically) and who have one or a few resectable metastases in the liver or lung should be considered for potential curative surgery. Alternatively, liver metastases that may not be surgically removed may potentially be controlled by a technique referred to as radiofrequency ablation (RFA). This procedure involves inserting a thin probe into the tumor and heating it with radiofrequency waves, thereby destroying the cancer cells. All patients treated by surgery or RFA for metastatic colorectal cancer should subsequently recieve adjuvant chemotherapy to further improve their chance for cure.

Surgery may relieve intestinal obstruction for patients in whom the primary tumor and/or metastases are extensive or unresectable. Other options to relieve intestinal obstructions without major surgery include laser recanalization or endoscopically placed stents.

Chemotherapy is the cornerstone of treatment for metastatic colorectal cancer that can not be surgically removed. The type of chemotherapy used depends on whether a patient has received previous chemotherapy for colorectal cancer. For example, if a patient's disease progresses during or within 6 months of receiving 5-fluorouracil-based chemotherapy, then irinotecan or enrollment into a clinical trial evaluating the efficacy of a new drug or novel drug combination should be offered. Alternatively, chemotherapy injected directly into the arteries of the liver (via an implantable pump surgically placed in the abdomen) may be appropriate in the setting of a clinical trial in patients whose metastases are confined to the liver.

Follow-up Care

Follow-up care after treatment for colorectal cancer is important. Regular checkups ensure that changes in health are noticed. If the cancer returns or a new cancer develops, it can be treated as soon as possible. Checkups may include a physical exam, a fecal occult blood test, a colonoscopy, chest x-rays, and lab tests. Between scheduled checkups, a person who has had colorectal cancer should report any health problems to the doctor as soon as they appear.

Specific Guidelines for Follow-Up Care

Patients who have been successfully treated for colon cancer should have a physical exam every 6 months for 2 years, then annually for 5 years. A blood test measuring CEA (carcinoembryonic antigen) should also be measured at the time of these visits if the CEA was elevated at the time of diagnosis or first treatment. A chest x-ray and a CT scan of the abdomen and pelvis should be done annually for 5 years in patients treated for stages II or III cancers, or every 6 months for those treated for stage IV disease. Colonoscopy is recommended 1 year after completion of treatment and should be repeated annually if new polyps are noted or every 3 years if not.

Guidelines for Evaluation of an elevated CEA

Colonoscopy, chest x-ray or chest CT scan, and CT scans of the abdomen and pelvis are indicated in patients whose CEA rises after surgery. Such surveillance is reasonable because a tumor recurrence in the liver, lung, or bowel may be successfully resected.

Where there are multiple or unresectable lesions, the standard intervention is chemotherapy using either a combination of fluorouracil and leucovorin or a continuous infusion of fluorouracil. For patients whose disease progresses while undergoing treatment with these agents or within 6 months afterward, standard options include chemotherapy with Irinotecan and/or supportive care.

Clinical Trials

Clinical trials (research studies) to evaluate new ways to treat cancer are an appropriate option for many patients with colorectal cancer. In some studies, all patients receive the new treatment. In other studies, a promising new treatment is given to one group of patients and the usual (standard) therapy to another group.

Research has led to many advances in the treatment of colorectal cancer. Through research, doctors explore new ways to treat cancer that may be more effective than the standard therapy. Clinical trials are an appropriate choice at any stage of disease management, since trials for screening, detection and prevention are also available. Find more information about Clinical Trials and current protocols available at Continuum Cancer Centers of New York.

The National Cancer Institute publication, "Taking Part in Clinical Trials: What Cancer Patients Need To Know" provides information about how these studies work. NCI's cancer information database contains detailed information about ongoing studies for colorectal cancer. NCI's Web site includes a section on clinical trials at http://cancer.gov/clinical_trials. This section provides both general information about clinical trials and detailed information about specific ongoing studies for colorectal cancer.