Treatment of Stage IV Rectal Cancer
Medically reviewed by Dr. C.H. Weaver M.D. Medical Editor (08/2018)
Following clinical evaluation of rectal cancer, the cancer is referred to as Stage IV rectal cancer 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.
Certain patients with Stage IV rectal cancer can be cured of their cancer and others derive meaningful palliative benefit from treatment. Patients with Stage IV rectal cancer can be broadly divided into two groups: those with cancer that may be possible to remove with surgery and those with more widespread cancer.
Treatment of Extensive Stage IV Rectal Cancer
While some patients have a single site of metastatic cancer that can be treated with curative intent, the majority of patients with Stage IV rectal cancer have more widespread cancer that cannot be completely removed with surgery.
If the cancer is extensive but not causing symptoms, treatment oven involves chemotherapy. Several different chemotherapy regimens are available, and the choice of which to use will depend on factors such as your health and previous treatment history. In some cases, chemotherapy may shrink the cancer enough that surgery to remove it becomes possible.
Chemotherapy may be given in combination with other drugs known as targeted therapies. Targeted therapies are anticancer drugs that interfere with specific pathways involved in cancer cell growth or survival. Some targeted therapies block growth signals from reaching cancer cells; others reduce the blood supply to cancer cells; and still others stimulate the immune system to recognize and attack the cancer cell. Depending on the specific “target”, targeted therapies may slow cancer cell growth or increase cancer cell death.
Targeted therapies that have shown a benefit for selected patients with metastatic colorectal cancer include Avastin® (bevacizumab), Erbitux® (cetuximab), and Vectibix® (panitumumab). Avastin blocks a protein (VEGF) that plays a key role in the development of new blood vessels. By blocking VEGF, Avastin deprives the cancer of nutrients and oxygen and inhibits its growth. Erbitux and Vectibix slow cancer growth by targeting a protein known as EGFR. Cancers with certain gene mutations are unlikely to respond to Erbitux or Vectibix, and tests are available to detect these mutations before treatment decisions are made.
If patients are experiencing symptoms from their rectal cancer, they may also receive treatments such as radiation therapy, surgery, or stenting to relieve problems such as bowel obstruction.
Treatment of Metastatic Rectal Cancer to a Single Site
Rectal cancer may spread (metastasize) to the liver, lung or other locations in the body. When the site of metastasis is a single organ, such as the liver or lungs, patients may benefit from local treatment directed at that single site of metastasis
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.
Treatment of the liver: The most common site of metastasis for patients with rectal cancer is the liver. When it’s possible to completely surgically remove all liver metastases, surgery is the preferred treatment. Some patients may have both the liver and the rectum treated in a single operation, and others may have two operations: one to treat the rectum and one to treat the liver. Chemotherapy or chemotherapy plus radiation therapy may be used before and/or after surgery.
Although surgery offers some patients the chance for a cure, a majority of patients with liver metastases are not candidates for surgery because of the size or location of their tumors or their general health. Some of these patients may become candidates for surgery if initial treatment with chemotherapy shrinks the tumors sufficiently. If the tumors continue to be impossible to remove surgically, other liver-directed therapies may be considered. These other therapies include radiofrequency ablation (use of heat to kill cancer cells), cryotherapy (use of cold to kill cancer cells), delivery of chemotherapy directly to the liver, and radiation therapy. Relatively little information is available from clinical trials about the risks and benefits of these other approaches, but they may benefit selected patients.1
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 continued participation in appropriate clinical trials. Currently, there are several areas of active exploration aimed at improving the treatment of rectal cancer.
New Approaches to Treating Liver Metastases: Researchers continue to explore news ways to treat cancer that has spread to the liver. One approach that is being evaluated is radioembolization This strategy uses radioactive microspheres (small spheres containing radioactive material). The small spheres are injected into vasculature of the liver, where they tend to get lodged in the vasculature responsible for providing blood and nourishment to the cancer cells. While lodged in place, the radioactive substance spontaneously emits radiation to the surrounding cancerous area while minimizing radiation exposure to the healthy portions of the liver.2 Researchers are also exploring alternatives to radiofrequency ablation for the destruction of liver tumors, as well as new approaches to delivering chemotherapy to the liver.
New Chemotherapy Regimens: Development of new multi-drug chemotherapy treatment regimens that incorporate new or additional anti-cancer therapies is an active area of clinical research.
New Approaches to Targeted Therapy: Targeted therapies such as Avastin, Erbitux, and Vectibix already play a role in the treatment of selected patients with advanced colorectal cancer, but researchers continue to explore new targeted therapies as well as new ways of using existing drugs. Developing tests to predict which patients are most likely to respond to which drugs is also an important focus of research. Tests to identify certain gene mutations in the cancer are already available, and can help guide the use of Erbitux and Vectibix.
1 Alsina J, Choti MA. Liver-directed therapies in colorectal cancer. Seminars in Oncology. 2011;38:651-567.
2 Hendlisz A, Van den Eynde M, Peeters M, et al. Phase III Trial Comparing Protracted Intravenous Fluorouracil Infusion Alone or With Yttrium-90 Resin Microspheres Radioembolization for Liver-Limited Metastatic Colorectal Cancer Refractory to Standard Chemotherapy. Journal of Clinical Oncology. 2010;28:3687-94.