|
|
|
Overview Following clinical evaluation of rectal cancer, a stage IV (D) rectal cancer is said to exist if the final evaluation shows that the cancer has spread to distant locations in the body which may include the liver, lungs, bones, or other sites. 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 IV 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 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. Patients diagnosed with stage IV rectal cancer have been perceived to have few treatment options. Certain patients, however, can still be cured of their cancer and others derive meaningful palliative benefit from additional treatment. Patients with stage IV rectal cancer can be broadly divided into two groups. Those with cancer that is localized to a single site and those with more widespread cancer. Treatment of Metastatic Rectal Cancer to a Single Site Rectal cancer may spread or metastasize to the liver, lung, or other locations in the body. When the site of metastases is a single organ such as the liver, patients may benefit from local treatment directed at that single site of metastases. The most common location of metastases for patients with rectal cancer is the liver. Highly selected patients with isolated areas of rectal cancer can be cured if the primary cancer in the rectum and the isolated area of cancer outside the rectum can be surgically removed. Several clinical trials have reported that patients with isolated areas of rectal cancer in the liver or lungs removed surgically are cured in approximately 25% of circumstances. Surgical removal of cancer can be accomplished with acceptable side effects in many community cancer centers with mortality rates of approximately 2%. Liver-Directed Therapies For Patients with disease confined to the liver who are not surgical candidates, several other liver-directed treatments approaches have been developed. The goal of liver-directed therapies are to inject chemotherapy directly into the blood supply of the liver thereby delivering chemotherapy directly to the cancer and/or block the flow of blood to the liver to further "starve" the cancer cells by preventing the necessary blood flow. Chemotherapy injected directly into the hepatic artery [hepatic artery infusion (HAI)] has the potential advantage of delivering higher doses of anti-cancer therapy directly to the cancer cells in the liver while avoiding the side effects of chemotherapy delivered systemically. Techniques that interrupt blood flow to the cancer cells in the liver can simply block (chemoemobilization) or closes the hepatic artery (hepatic artery ligation). These liver-directed treatment approaches are all highly specialized procedures and when performed by experienced individuals in highly selected patients have produced some encouraging treatment results. In order for these procedures to become widely used, the risk and benefit of liver-directed therapies must outweigh the risk and benefit from standard surgical removal of isolated liver lesions and systemic chemotherapy. Hepatic Artery Infusion: Hepatic artery infusion has been the most widely evaluated of the liver-directed treatment strategies. The most commonly used chemotherapeutic agent infused into the hepatic artery is FUdR. A clinical study in patients with cancer confined to the liver compared hepatic artery infusion with FUdR to no additional treatment. The study demonstrated that patients treated with hepatic artery infusion survived on average 13.5 months compared to 7.5 months for patients receiving no additional treatment. Hepatic Artery Infusion and Systemic Chemotherapy: When rectal cancer has spread to the liver, it is likely that cancer may exist elsewhere in the body; therefore, many doctors have advocated giving systemic chemotherapy over hepatic artery infusion chemotherapy directed exclusively to the cancer cells in the liver. Several clinical studies have been performed in patients with cancer metastatic to the liver which compare hepatic artery infusion with FUdR to treatment with systemic 5-fluorouracil-based chemotherapy. An analysis of all these trials together has demonstrated that hepatic artery infusion produces a higher remission rate than systemic chemotherapy; however, the average overall survival is not significantly improved. Patients treated with hepatic artery infusion lived on average 16 months compared to 12 months for patients treated with systemic 5-fluorouracil chemotherapy. One clinical trial has compared the effectiveness of hepatic artery infusion and systemic infusion of chemotherapy administered into a vein versus systemic infusion chemotherapy alone. Physicians randomly allocated 156 patients with colorectal cancer to two groups. One group received 6 cycles of chemotherapy into the hepatic artery and systemic chemotherapy while the other group only received systemic chemotherapy. The survival was 86% at 2 years for patients receiving treatment with hepatic artery infusion and systemic chemotherapy and 72% for patients receiving systemic chemotherapy alone. The average survival was 72 months for the combined treatment and 59 months for systemic chemotherapy treatment alone. Only 10% of patients receiving combined treatment develop a cancer recurrence compared to 60% of patients receiving the systemic chemotherapy treatment alone. The combined therapy did not lead to an increased mortality. In summary, for patients with rectal cancer isolated to the liver who are unable to undergo surgical removal of the cancer, hepatic artery infusion improves response rates and prolongs survival when compared to no treatment and may produce a minor survival advantage compared to patients treated with systemic 5-fluorouracil chemotherapy. Treatment of Non-Localized Stage IV Rectal Cancer While some patients have a single site of cancer that can be treated with curative intent, the majority of patients have unresectable or widespread cancer. Historically, these patients have been considered incurable and were offered treatment with chemotherapy for the purpose of prolonging their duration of survival and alleviating symptoms from progressive cancer. Single-agent 5-fluorouracil chemotherapy with or without leucovorin was the standard treatment approach for over 30 years. Treatment with 5-fluorouracil chemotherapy regimens induce a remission or shrinkage of the cancer in 15-45% of patients and the average patient survives approximately 1 year from treatment. Continuous infusion 5-fluorouracil appears to have less toxicity and provides more benefit than rapid intravenous infusion 5-fluorouracil therapy. The biologic agent interferon has also been combined with 5-fluorouracil and leucovorin and evaluated in clinical trials. The addition of interferon did not prolong a patients survival and may have diminished patients quality of life. Patients electing to receive treatment with 5-fluorouracil should discuss the potential side effects from treatment as they vary considerably across the many different 5-fluorouracil chemotherapy regimens. More recently, several newer chemotherapeutic drugs have demonstrated a substantial ability to kill rectal cancer cells in patients with recurrent cancer. Developing and exploring single or multi-agent chemotherapy agents as a treatment approach for patients with widespread rectal cancer is an area of active investigation. A newer chemotherapy drug, CPT-11, has been compared to the best supportive care available in patients with colorectal cancer that no longer responded to chemotherapy with 5-fluorouracil. In this direct comparison, patients receiving CPT-11 treatment were 2.6 times more likely to be alive after 1 year of treatment. This clinical study established CPT-11 as a standard treatment for patients with colorectal cancer. More recently, French researchers assigned 387 previously untreated patients with advanced cancer of the colon or rectum to receive either A) fluorouracil and calcium folinate plus Camptosar® or B) fluorouracil and calcium folinate alone. The results showed a response rate of 49% for patients receiving both Camptosar® and fluorouracil compared with 31% for patients receiving fluorouracil alone. The time it took for the cancer to progress (begin growing again) was also more delayed in patients receiving the Camptosar® (6.7 versus 4.4 months). The average survival time was 17.4 months for patients receiving Camptosar® and fluorouracil compared with 14.1 months for those receiving fluorouracil alone. The Camptosar® regimen had more side effects; however, all were manageable and reversible. These findings show response rates in patients receiving Camptosar® plus fluorouracil/calcium folinate that are superior to those in patients receiving fluorouracil/calcium folinate alone. There were also modest increases in the time it took for the cancer to progress and in survival. The researchers concluded that this new regimen should be considered an option for the primary treatment of advanced colorectal cancer. Strategies to Improve Treatment While some progress has been made in the treatment of Stage IV rectal cancer, the majority of patients still succumb to cancer and better treatment strategies are clearly needed. Future progress in the treatment of rectal cancer will result from patients continuing to participate in appropriate clinical trials. Areas of active exploration to improve the treatment of 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." |
