|
|
|
Overview Following surgical removal of rectal cancer a stage III or C rectal cancer is said to exist if the final pathology report, after looking under the microscope, shows that the cancer has penetrated the wall of the rectum and invaded any of the local lymph nodes but 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 III rectal 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 Clinical News web site feature presents the results of the actual clinical trials that determine the standard treatments of rectal cancer and new treatment strategies as they have been discovered and applied by cancer physicians around the world. All new treatments are developed 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. Surgical Treatment Stage III (C) adenocarcinoma of the rectum is a curable cancer. Depending on features of the cancer under the microscope, approximately 40% of patients are cured without evidence of cancer recurrence following treatment with surgery alone. The standard surgical procedures used to remove stage III rectal cancer include low anterior resection (LAR) or abdominoperineal resection (APR). The choice of operation depends on the location of the rectal cancer in relation to the rectal sphincter or anus. For cancers that are located well-above the anus, an LAR procedure can be performed. Following LAR procedure, the cut ends of the rectum are sewn together and anal function is preserved. For cancers close to the anus, an APR procedure is often necessary. Following an APR procedure, the anus is removed with the cancer, and the cut end of the large bowel is attached to the abdominal wall to form a permanent colostomy. The colostomy is covered by a bag, which collects stool as it empties from the bowel. Because of the inconvenience of a colostomy, cancer doctors are using sphincter-sparing treatments that allow the patient to keep the anus. To learn more, go to Surgical Management of Rectal Cancer. Despite the cancer being completely resected surgically, 60-70% of patients with stage III rectal cancer experience recurrence of their cancer. It is important to realize that many patients with stage III disease already had small amounts of cancer that had spread outside the rectum 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 rectum are referred to as micrometastases. It is the presence of these microscopic areas of cancer 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. Adjuvant Therapy A combination of chemotherapy and radiation therapy is often administered after surgery to cleanse the area of the operation of microscopic cancer cells that may be remaining. The decision to treat with chemotherapy and radiation therapy after excision is based on the depth of invasion of the cancer and how aggressive the cancer appears under the microscope. This treatment for cancer given following surgery for the purpose of reducing cancer recurrences is referred to as adjuvant therapy. Adjuvant therapy for rectal cancer typically involves both radiation therapy and the use of one or more anti-cancer drugs or chemotherapy. Adjuvant 5-fluorouracil chemotherapy and radiation therapy have been used as treatment for patients with stage III rectal cancer to reduce cancer recurrences. Clinical trials have shown that treatment with adjuvant 5-fluorouracil chemotherapy and radiation therapy improves survival compared to treatment with surgery alone. A clinical trial performed by doctors in the Gastrointestinal Tumor Study Group (GITSG) directly compared surgery to surgery followed by chemotherapy, radiation therapy in patients with stage II and III rectal cancer. This clinical trial demonstrated an improvement in patient survival when 5-fluorouracil chemotherapy and radiation therapy were used after surgery compared to patients treated with surgery alone. Patients were treated with external beam radiation therapy to the pelvis and 5-fluorouracil chemotherapy was administered before, during, and after radiation therapy for a total of 18 months. Patients treated with this adjuvant chemoradiation approach had a 6-year survival rate of about 54% compared with a survival rate of 27% in patients treated with surgery alone. Another clinical trial conducted by the North Central Cancer Treatment Group (NCCTG) directly compared adjuvant radiation therapy alone with adjuvant radiation therapy and chemotherapy following surgery for advanced rectal cancer. The addition of chemotherapy to radiation therapy reduced the chance of cancer recurrence. The use of combined adjuvant chemoradiation improved the 7-year survival in patients from 38%, using radiation therapy alone, to 49% when both chemotherapy and radiation were used. These and other clinical trials taken together demonstrate that adjuvant 5-fluorouracil chemotherapy for 6 months and radiation therapy following surgical resection of patients with stage II (B2, B3) rectal cancer improves a patient's chance of cure and overall survival. More recent clinical trials have investigated more effective methods to administer chemotherapy to further improve survival. A second clinical trial conducted by the NCCTG directly compared adjuvant chemoradiation using 5-fluorouracil given every few weeks (bolus) with adjuvant chemoradiation using 5-fluorouracil given continuously. 5-fluorouracil is given continuously using a portable chemotherapy pump attached to a permanent intravenous line. There was a 10% improvement in survival in the group of patients treated with continuous infusion 5-fluorouracil chemotherapy compared with patients treated with bolus 5-fluorouracil chemotherapy. Although continuous infusion 5-fluorouracil chemotherapy produced a higher cure rate, there were also more side effects including diarrhea and lowered blood counts. Neoadjuvant Therapy Rectal cancer may not be diagnosed until it has grown to the point that surgery would be unlikely to result in complete removal of the cancer. These cancers that lie close to the anus can be treated before surgery to permit an operation that preserves the rectal sphincter or anus. A combination of chemotherapy and/or radiation therapy administered before surgery to help shrink the cancer is referred to as neoadjuvant therapy. The chemotherapy and/or radiation therapy is delivered in a manner similar to treatment following surgery. If there is sufficient shrinkage with the neoadjuvant therapy, a low anterior resection can be performed to remove the rectal cancer and preserve the anus. Neoadjuvant therapy is important because when surgery is not feasible, the possibility of cure is reduced. Some clinical studies have determined that neoadjuvant therapy can increase the chance of complete surgical removal of the cancer and improve a patient's chance of cure. In one clinical trial, 30 patients with locally advanced (stage II-III) rectal cancer received chemotherapy with a drug called UFT and leucovorin as well as radiation therapy before surgery the results showed that 71% had a response with 14% being complete. The cancer was "down staged" in 53% of patients allowing for a less drastic type of surgery to be performed. The benefits of neoadjuvant therapy compared with adjuvant therapy after surgical resection are being evaluated in ongoing clinical trials. Strategies to Improve Treatment The progress that has been made in the treatment of rectal cancer has resulted from improved surgical techniques and development of adjuvant chemotherapy treatments and participation in clinical trials. Future progress in the treatment of rectal cancer will result from patients and doctors continuing to participate in appropriate clinical trials. Areas of active exploration to improve the treatment of stage III or C rectal cancer include the following:
USED WITH PERMISSION OF CANCERCONSULTANTS.COM 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." |
