Colon Cancer Stage 2

Following surgical removal of colon cancer, a stage II (B) colon cancer is said to exist if the final pathology report shows that the cancer has penetrated the wall of the colon into the abdominal cavity but does not invade any of the local lymph nodes and cannot be detected in other locations in the body.

A variety of factors ultimately influence a patient’s decision to receive treatment of cancer. The purpose of receiving cancer treatment may be to improve symptoms through local control of the cancer, increase a patient’s chance of cure, or prolong a patient’s survival. The potential benefits of receiving cancer treatment must be carefully balanced with the potential risks of receiving cancer treatment.

The following is a general overview of the treatment of stage II colon cancer. Circumstances unique to your situation and prognostic factors of your cancer may ultimately influence how these general treatment principles are applied to your situation. In addition to this treatment overview, the Cancer Treatment News web site feature presents the results of the actual clinical trials that determine the standard treatments of colon cancer and new treatment strategies as they have been discovered and applied by cancer physicians around the world.

All new treatments are evaluated in clinical trials. Participation in a clinical trial may offer access to better treatments and advance the existing knowledge about treatment of this cancer. Remember, this web site information is intended to help educate you about your treatment options and to facilitate a mutual or shared decision-making process with your treating cancer physician.

Stage II (B) adenocarcinoma of the colon is a common and curable cancer. Depending on features of the cancer, 60-75% of patients are cured without evidence of cancer recurrence following treatment with surgery alone. According to the National Cancer Institute (NCI), standard treatment of patients with stage II (B) colon cancer is considered to be surgical resection and no adjuvant therapy or enrollment on a clinical trial evaluating adjuvant therapy.

Despite the cancer being completely resected surgically, 25-40% of patients with stage II colon carcinoma experience recurrence of their cancer. It is important to realize that many patients with stage II disease already have small amounts of cancer that have spread outside the colon and were not removed by surgery. These cancer cells cannot be detected with any of the currently available tests. Undetectable areas of cancer outside the colon are referred to as micrometastases. It is the presence of micrometastases that causes the relapses that follow treatment with surgery alone. An effective treatment is needed to cleanse the body of micrometastases in order to improve the cure rate achieved with surgical removal of the cancer. Efforts are currently underway to find such a therapy.

Adjuvant Chemotherapy Treatment

Adjuvant chemotherapy is the use of one or more anti-cancer drugs following surgery for the treatment of cancer. Adjuvant chemotherapy has been used as treatment for patients with stage II and III colon cancer for the purpose of reducing cancer recurrences.

colorectal cancer stages

The NCI recommendation of no adjuvant chemotherapy is based on several clinical trials that show inconsistent results regarding treatment of stage II (B) colon cancer. Some clinical trials have shown that treatment with adjuvant chemotherapy improves survival and some show no benefit compared to treatment with surgery alone. This is in contrast to patients with stage III (C) colon cancer where treatment with fluorouracil-based adjuvant chemotherapy compared to no adjuvant therapy has consistently demonstrated an improvement in recurrence-free and overall survival. The lack of benefit observed in some trials may be because stage II and III patients are included in the same trial evaluating adjuvant treatment. Because small numbers of patients with stage II cancer are enrolled, the trial may not detect a benefit from treatment. NCI-sponsored trials through the NSABP, however, have consistently shown a trend toward improved survival in stage II (B) patients treated with adjuvant chemotherapy.

In the NSABP trials, treatment with 6 months of fluorouracil and Leucovorin chemotherapy produces a 5-year survival rate for approximately 85-90% for patients with stage II (B) colon cancer compared to a 70-74% survival for patients treated with surgery alone. Other adjuvant chemotherapy regimens have been demonstrated to be equivalent to fluorouracil and Leucovorin administered for 6 months. None, however, have been shown to be superior, and these other regimens use higher doses of chemotherapy drugs with an increase in associated side effects or a longer duration of treatment (12 months). Taken together, adjuvant fluorouracil /Leucovorin chemotherapy treatment for 6 months following surgical resection of patients with stage II (B) colon cancer appears to improve a patient’s chance of cure and overall survival.

Strategies to Improve Treatment

The progress that has been made in the treatment of colon cancer has resulted from improved development of adjuvant chemotherapy treatments and  participation in clinical trials. Future progress in the treatment of colon cancer will result from patients and doctors continuing to participate in appropriate clinical trials. Areas of active exploration to improve  the treatment of stage II or B colon cancer include the following administered alone or in combination:

New Adjuvant Treatment Regimens:  Undetectable areas of cancer outside the colon are referred to as micrometastases. It is the presence of micrometastases that causes the cancer to relapse following treatment with surgery. Improved adjuvant treatment approaches can further increase the approximate cure rate achieved with surgical removal of the cancer and include the following:

New Chemotherapy Regimens: Several new chemotherapy drugs show promising activity for the treatment of colon cancer. Development of new multi-drug chemotherapy treatment regimens that incorporate these new or additional anti-cancer therapies for use as adjuvant treatment is an active area of clinical research. Because treatment with Camptosar® combined with 5FU/LV has been shown to improve response rates and prolong survival when compared to treatment with 5FU/LV alone in patients with more advanced cancer, clinical trials are ongoing to determine whether Camptosar® 5FU/LV can increase the chance of cure in patients with stage III disease.

 

Biological Modifier Therapy: Biologic response modifiers are naturally occurring or synthesized substances that direct, facilitate, or enhance your body’s normal immune defenses. Biologic response modifiers include interferons, interleukins, and monoclonal antibodies. In an attempt to improve survival rates, these and other agents are being tested alone or in combination with chemotherapy in clinical studies. Interferon has been combined with fluorouracil and Leucovorin and evaluated in colon cancer. The addition of interferon to fluorouracil /Leucovorin did not improve survival or decrease the risk of relapse compared to fluorouracil and Leucovorin alone. 

 

Monoclonal Antibodies: Another approach is to deliver additional treatment directed specifically to the cancer cells and avoid harming the normal cells. Monoclonal antibodies are a treatment that can locate cancer cells and kill them directly. Monoclonal antibodies are being evaluated alone or  in combination with chemotherapy to determine whether they can improve cure rates. The 17-IA monoclonal antibody has been shown to improve survival in patients with colorectal cancer in Germany. Although not available in the United States, clinical trials are ongoing  throughout the world to further evaluate the 17-IA monoclonal antibody.

Vaccines: The purpose of a vaccine is to help the patient’s immune system destroy the cancer by activating the patient’s immune cells against the cancer. Vaccines are made from a variety of substances that often include the actual cancer cells removed from the patient.  A difficulty in preparing vaccines is that the patient’s cancer cells must be processed immediately following surgery.   Patients and their surgeons must therefore prepare in advance to ensure the removed cancer cells can be handled properly for vaccine preparation. Vaccines have already been shown to improve the survival of certain patients with colon cancer and continue to be evaluated in clinical trials.

Improvement in Predicting Need for Adjuvant Chemotherapy: Although staging is important in order to determine proper treatment and outcome, current tests are not reliable enough to predict patients who will relapse if they do not receive adjuvant chemotherapy or chemo radiotherapy. Doppler ultrasound has been used to measure blood flow in the artery to the liver (hepatic artery) and total liver flow in patients with rectal cancer. This measurement is helpful because abnormalities occurring in hepatic artery blood flow can be used to detect early cancer metastasis to the liver. This technique is particularly important for patients with colorectal cancer because the current strategy does not allow doctors to accurately predict which patients will experience a metastasis. In one recent clinical study, 120 patients with colorectal cancer underwent curative surgery. Patients with stage I (A) or II (B) cancer had a recurrence-free survival rate of 57% and patients with stage III (C) had a recurrence-free survival of 39%. Of the 49 patients who had a normal Doppler perfusion in before surgery, the survival was 89% with no recurrence of cancer. Of 73 patients who had an abnormal value, only 22% survived with no recurrence of cancer. This study suggests that Doppler perfusion can identify patients who need additional treatment.

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copyright® 1998, last updated 01/01, CancerConsultants.com – All Rights Reserved.

“The information contained above is  general in nature and is not intended as a guide to self-medication by consumers or meant to substitute for advice provided by your own physician or other medical professional. The reader is advised to consult with a physician or other medical professional and to check product information (including packaging inserts) for changes and new information regarding dosage, precautions, and contra indication before administering any drug, herb, supplement, compound, therapy or treatment discussed herein. Neither the editors nor the publisher accepts any responsibility for the accuracy of the information or consequences from the use or misuse of the information contained herein.”

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