Colon cancer treatments vary based on the stage of your cancer. That’s because the stage of colorectal cancer tells your oncologist how far the cancer has grown. The cancer care team will use this information along with other important factors such as biomarker test results, to develop a plan that can most effectively treat the specific stage of your cancer.
Finding cancer early is proven to give you the best chance of a cure and reduces cancer deaths. Early detection also provides more options for treatment and makes treatments easier to endure.
How is Colon Cancer Diagnosed?
There are two common ways colon cancer is diagnosed. The first is if symptoms appear. Because colon cancer grows for a while before showing symptoms these patients may already have advanced colon cancer.
The other way many colon cancers are identified is through a screening colonoscopy. During a colonoscopy, the doctor can remove any polyps that look suspicious so they can be evaluated by a pathologist. This doctor looks at the tissue collected under a microscope to determine how different cells have become compared to normal cells. If cancer is found, it’s typically at a much earlier stage compared to colon cancer that’s found after symptoms appear.
You may also be interested in reading our blog: What to Do After a Colorectal Cancer Diagnosis
Staging is Part of the Cancer Diagnosis Process
Once colorectal cancer is diagnosed, your oncologist will determine the stage of cancer. Staging identifies the extent of the cancer including whether it has spread to lymph nodes and/or other nearby organs. Imaging scans of the chest, pelvic area, or abdomen are taken using computed tomography (CT) or ultrasound. This indicates whether there is cancer outside of the colon.
In many cases, getting a definitive colon cancer stage is not possible until after cancer surgery to see if lymph nodes were affected and to see how far the cancer cells penetrated into the wall of the colon.
Surgical staging means the cancer’s stage is determined by tissue removed during surgery. This is the most accurate method. Clinical staging, which is less accurate, is based on a physical exam, biopsy, and CT scans done before surgery.
The Staging System for Colon Cancer
Most oncologists use the TNM staging system to determine the stage:
- T stands for tumor size or extent and assesses how far the cancer has grown into the multiple layers of the colon lining and the tumor’s size and location.
- N stands for lymph nodes and indicates if it has spread or affected the lymph nodes.
- M is for metastasis and measures the amount of spread to distant parts of the body.
After the T, N, and M values are established, they are combined to provide an overall cancer stage. Stages are assigned a Roman numeral from 0 to IV (4). Zero is the lowest stage and four indicates the most advanced. The lower the stage, the better the outcomes are likely to be.
Additional letters are included to indicate subtle degrees of spread within the five stages. For example, stage IIB cancer has slightly less spread than IIC cancer.
What are the Different Stages of Colorectal Cancer?
The five stages of colorectal cancer are summarized here:
- 0 is the earliest stage. The cancer has not spread beyond the most inner layer of the colon or rectum.
- Stage I indicates that cancer has grown into deeper layers of the colon, but not spread to lymph nodes.
- Stage II (2)
- IIA means the cancer has grown into the outermost layers of the colon but not through them and has not affected lymph nodes.
- IIB stage cancer has grown through the colon or rectal wall, but not into nearby tissues or lymph nodes.
- IIC means it has grown through the wall and into nearby tissues or organs, but not affected lymph nodes.
- Stage III (3)
- IIIA indicates that it has spread to four to six lymph nodes.
- IIIB cancer has spread to more lymph nodes but not to distant sites.
- IIIC cancer has grown into nearby tissues or organs and lymph nodes, but not to distant organs.
- Stage IV (4)
- IVA cancer may or may not have grown through the colorectal wall or nearby lymph nodes. It has spread to at least one other organ or distant lymph node, but not to the lining of the abdomen.
- IVB stage cancer is similar to 4A but includes spreading to more than one distant organ or lymph node.
- IVC is like 4B cancer but includes spread to the abdominal lining and possible distant organs or lymph nodes.
How Does the Cancer’s Stage Affect Treatment?
The treatment guidelines established for colon cancer are determined by the cancer’s stage. The stage of cancer also impacts:
- The recommended order of treatments and which treatments are likely to be the most effective
- Your prognosis, or likelihood of survival
- Your eligibility for entering a clinical trial
Post-therapy staging is used when other treatments (radiation, chemotherapy, immunotherapy, or hormone therapy) are given before surgery to shrink tumors. A second staging helps determine how well treatments are working and assists in planning additional treatments.
What are Colon Cancer Treatment Options by Stage?
- Stage 0 cancers, which are very small, are usually removed with minimally invasive surgery. This includes removing polyps during a colonoscopy. Endoscopic mucosal resection removes larger polyps along with some of the colon’s inner lining. Laparoscopic surgery, used for larger polyps, removes polyps via tiny incisions in your abdomen. Removing a part of the colon (partial colectomy) is done if the cancer is too large for removal using a local incision. Surgery is usually the only treatment for stage 0.
- Stage 1 cancers, which are usually inside a polyp, require removal during a colonoscopy. If there are cancer cells in the immediate area of the polyp, or the entire polyp could not be removed, additional surgery may be needed. Stage 1 cancers that aren’t in a polyp require surgery to remove a section of the colon and nearby lymph nodes (partial colectomy).
- Stage 2 cancers require removal using a partial colectomy (removing part of the colon) plus nearby lymph nodes to be checked for cancer cells. Chemotherapy after surgery is used if the cancer has a high risk of returning.
- Stage 3 cancers require surgery to remove the cancerous section of the colon and nearby lymph nodes, plus chemotherapy after surgery. More advanced cancers and those that cannot be removed completely with surgery are also treated with radiation and chemotherapy. Chemotherapy and/or radiation are also options for patients who cannot undergo surgery.
- Stage 4 colon cancers have spread to distant organs and tissue, most commonly the liver, lungs, brain, lining of the abdominal cavity, or distant lymph nodes. Surgery is not expected to cure stage 4 cancer, but it can help patients live longer. It’s usually followed by chemotherapy.
For very large stage 4 cancers, chemotherapy is used to shrink tumors to increase the chance that they can be surgically removed. If the cancer has spread too far for surgical removal, chemotherapy is the main treatment. If a stage 4 cancer is blocking the colon, a colostomy will be created to provide an opening in the skin to expel waste matter.
Targeted therapies can help slow the growth of the cancer. The right one for each patient is based on the results of the biomarker testing process. Biomarker testing indicates which gene has mutated and can be targeted with a drug that slows the cancer’s growth.
Radiation can relieve symptoms such as pain. Advanced cancers can also be treated with targeted drug therapy, which is usually combined with chemotherapy or immunotherapy.
Clinical Research Trials are Available for Colon Cancer
Participating in a clinical research trial is possible for some patients depending on the stage and previous treatments, if any. These trials offer new treatment options unavailable otherwise. You will be offered the opportunity to participate if one is available to you. You will never be added to a trial without your permission.
Palliative Care… Not Just for End of Life
Palliative care focuses on relieving pain and other symptoms of cancer. It’s often confused with end-of-life care but it’s actually useful at any stage of colorectal cancer. The goal of palliative care is to improve the patient's quality of life by reducing symptoms including managing pain caused by the cancer. It can be given at any time during cancer treatment, including right after cancer is diagnosed or after cancer treatment is completed.
Personalized Colon Cancer Treatments by Stage for Patients in Colorado
Because every patient and every cancer is unique, it’s important to have a treatment plan designed just for you. Personalized treatment considers unique factors, such as your age, overall health, and other health conditions or diseases, to plan your treatment.
The GI oncologists at Rocky Mountain Cancer Centers focus on colon and rectal cancers, creating personalized treatment plans using the latest developments in colon cancer treatments for every stage.
Request an appointment today at any of our convenient locations in Aurora, Boulder, Castle Rock, Centennial, Colorado Springs, Denver, Englewood, Lakewood, Littleton, Lone Tree, Longmont, Steamboat Springs, or Thornton, Colorado.