The minute your doctor pronounces his diagnosis that you have colon cancer, it’s only natural that you start feeling apprehensive about your prospects for survival. You end up asking your doctor numerous questions about your prognosis. Your doctor answers them based on statistical data on prognosis and survival rates available in the field, which are derived from large populations of people. However, you should understand that statistical data cannot accurately predict an individual’s survival rate.

What Is Colon Cancer Survival Rate?

Colon cancer can be effectively treated if diagnosed in the early stages but the disease is difficult to treat when diagnosed at the later stages. Below is a description about survival rate for colon cancer in different stages (the survival rate for cancer patients is given in terms of 5 year survival rate which is the percentage of people who live at least five years after being diagnosed with cancer):

Stage 0: The cancer is present in the innermost layer of the colon. When diagnosed at this stage, the cancer and the surrounding tissues can be removed by surgery and the patient is completely cured.

Stage I: At this stage the cancer has spread to the 2^nd and 3^rd layers of the colon and has even reached the inside walls of the colon. The patient has a 93% five year survival rate when diagnosed with stage I colon cancer.

Stage II: Colon cancer has spread to the muscular walls of the colon and has not yet reached the lymph nodes. The five year colon cancer survival rate for patients diagnosed with stage II colon cancer is 78%.

Stage III: At this stage, the cancer has spread from the colon to the lymph nodes. Stage III colon cancer is further divided into:

• III A: Tumors are confined within the walls of the colon but the lymph nodes are also affected.
• III B: Tumors have spread from the colon to at least four lymph nodes.
• IIIC: Tumors have spread from the colon to more than four lymph nodes.

Patients who have less number of lymph nodes affected have a better chance for survival. Patients diagnosed with stage III colon cancer have a 5 year survival rate of 64%. 

Stage IV: In stage IV colon cancer the cancer has spread to the organs like liver and lungs. The lymph nodes may or may not be affected. The 5 year survival rate of patients diagnosed with stage IV colon cancer is 8%.

Other Factors That Affect the Survival Rate

There are several factors that affect the colon cancer survival rate:

• Cancer grade: It is an indication of how close the cancer cells resemble the normal cells. Low grade cancers bear close resemblance to normal cells and have a better treatment outcome. The high grade cancers are abnormal and differ a lot from normal cells.
• Lymph nodes: In colon cancer, the cancer has the possibility of spreading to the lymph nodes. If the number of lymph nodes that are affected by the cancer is high, then there is a higher chance of recurrence of cancer.
• General fitness: Your general fitness level at the time of diagnosis determines your ability to endure the rigorous treatment regimen for colon cancer. If your fitness levels are high at the time of diagnosis, then there is a higher chance of the treatment having a positive outcome.
• Colon blockage: If colon cancer blocks your colon or creates a hole in your bowel, it can impact your survival rate.
• Carcinoembryonic antigen (CEA): CEA is a protein molecule present in the blood. The levels of CEA increase when cancer of colon is present. Increased levels at the time of diagnosis affectyour response to treatment.

Understanding Survival Rate

You should understand that statistics cannot predict your individual treatment outcome. A generalized prediction of how the disease progresses can be made using statistical data but it has its limitations. Colon cancer affects each one differently and your experience with colon cancer can be entirely different from another person’s experience.

Moreover, the treatment options for colon cancer are evolving constantly and new clinical trials are being done to develop more effective medications. The effect of these new treatment options on life expectancy may take years to understand completely. The statistical data available to your doctor may not include the impact of the latest therapeutic developments which may increase the colon cancer survival rate.

Colon Cancer Treatment at Different Stages

Stage 0 Colon Cancer

The treatment for this cancer includes two surgical methodologies called polypectomy and anastomosis. In polypectomy the surgeon removes the tumor in the colon and a little of the surrounding areas of the colon. Anastomosis is done if the tumor size is large. The surgeon removes the cancer affected parts of the colon entirely and reconnects the healthy parts to enable the bowels to function normally.

Stage I Colon Cancer

Similar to stage 0, stage I colon cancer is treated by surgery where the tumor and its surrounding tissues are removed. At this stage, additional treatment is generally not required.

Stage II Colon Cancer

In case of stage II colon cancer, surgery is done to remove the tumor and its adjacent tissues. The doctor may also recommend chemotherapy to prevent the cancer from relapsing. Chemotherapy is usually recommended for people who have a high chance of relapse.

Stage III Colon Cancer

In Stage III colon cancer where lymph nodes are also affected, treatment involves:

• Surgery to remove the cancer and all the affected lymph nodes
• Chemotherapy after the surgery is performed
• Radiation therapy if the tumor was large and invaded the surrounding tissues

Stage IV Colon Cancer

For stage IV colon cancer where the cancer has spread or metastasized to other organs in the body like the liver and lungs, the following treatments are needed:

• Surgery is done to remove the cancer in the colon and the cancer that has spread to other organs. Anastomosis is also done on the patients if needed.
• Chemotherapy is administered and along with chemotherapy the following drugs are also given. Monoclonal antibodies like Bevacizumab (Avastin), cetuximab (Erbitux), or panitumumab (Vectibix) may be given; they have an impact on your immune system.  Ziv-Aflibercept (Zaltrap) is recommended if your cancer is not responding to other treatments.  
• If your cancer has metastasized to other organs in spite of treatment, your doctor may recommend targeted therapy. Regorafenib (Stivarga) is the drug given in targeted therapy.
• Radiation is also recommended for stage IV colon cancer.