Following colon cancer surgery, the cancer is classified as a Stage I colon cancer if the final pathology report shows that the cancer is confined to the lining of the colon. Stage I cancer does not penetrate the wall of the colon into the abdominal cavity, has not spread to any adjacent organs or local lymph nodes and cannot be detected in other locations in the body.
Depending on features of the cancer under the microscope, Stage I colon cancer survival rates are high: approximately 90% of patients are cured with colorectal surgery alone and will not have evidence of cancer recurrence.
Despite undergoing surgical removal of the cancer, a minority of patients with Stage I colon cancer may experience recurrence of their cancer. It is important to realize that a few patients with Stage I 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. The presence of micrometastases causes the relapses that follow treatment with surgery alone. An effective treatment is needed to eliminate micrometastases in order to improve the cure rate achieved with surgical removal of the cancer. Efforts are currently underway to find such a therapy.
The following is a general overview of treatment for Stage I colon cancer. Treatment may consist of surgery with or without adjuvant (post-surgery) treatment. Multi-modality treatment, which is treatment using two or more techniques, is increasingly recognized as an important approach for increasing some patients’ chance of cure or prolonging survival. In some cases, participation in a clinical trial utilizing new, innovative therapies may provide the most promising treatment. Circumstances unique to each patient’s situation may influence how these general treatment principles are applied and whether the patient decides to receive treatment. The potential benefits of multi-modality care, participation in a clinical trial, or standard treatment must be carefully balanced with the potential risks. The information on this Web site is intended to help educate patients about their treatment options and to facilitate a mutual or shared decision-making process with their treating cancer physician.
Surgery to remove the cancer is the primary treatment for Stage I colon cancer. In some cases, it’s possible to completely remove a cancerous colon polyp during colonoscopy. In other cases, colon cancer surgery may involve open surgery (which involves a single large incision) or laparoscopic surgery (which involves several small incisions).
The delivery of cancer treatment following local treatment with surgery is referred to as “adjuvant” therapy and may include chemotherapy, radiation therapy and/or targeted therapy. Adjuvant chemotherapy is commonly used for patients with Stage III colon cancer and may also be used in selected patients with Stage II colon cancer. The goal of chemotherapy in these patients is to reduce the risk of cancer recurrence. Thus far, clinical trials have not been performed evaluating adjuvant treatment in patients with Stage I cancers because of the very high cure rate achieved with surgery alone.
STRATEGIES TO IMPROVE TREATMENT
The development of more effective cancer treatments requires that new and innovative therapies be evaluated with cancer patients. Clinical trials are studies that evaluate the effectiveness of new drugs or treatment strategies. Future progress in the treatment of Stage I colon cancer will result from the continued evaluation of new treatments in clinical trials. Participation in a clinical trial may offer patients access to better treatments and advance the existing knowledge about treatment of this cancer. Patients who are interested in participating in a clinical trial should discuss the risks and benefits of clinical trials with their physician. Areas of active exploration to improve the treatment of Stage I colon cancer include the following:
Improvement in Predicting Need for Adjuvant Therapy: Undetectable areas of cancer outside the colon are referred to as micrometastases. The presence of micrometastases may cause the cancer to relapse following treatment with surgery alone, but physicians currently cannot predict which patients will relapse.
Adjuvant chemotherapy has been shown to decrease the risk of cancer recurrence in patients with Stage III colon cancer, but benefits in patients with Stage I cancer — who have a high rate of cure with surgery alone — have not been demonstrated. New methods of determining which patients with early-stage colon cancer are at highest risk of cancer recurrence may identify a subset of patients who could potentially benefit from adjuvant treatment. A test that is being used for some patients with Stage II colon cancer is the Oncotype DX colon cancer test. The test estimates the risk of cancer recurrence by evaluating the activity of certain genes in a sample of tumor tissue.