Before you get tangled up in statistics, remember one vital concept: Colon cancer survivors are human beings, individuals, real people – not just numbers. Survival rates are the number, measured in percentages, of people who have lived past a certain number of years with colon cancer. The most common time reference used for colon cancer survival rates is five years.
Disease-Specific Survival Versus Standard Survival
There are two terms used when doctors talk about survival rates, including the disease-specific survival rate and the standard survival rate. The standard survival rates for colon cancer include everyone, regardless of whether they died of natural causes, a car accident or from the colon cancer. The disease-specific survival rates are more specific, as these numbers only represent deaths from colon cancer and do not include the people who died of other causes. If you don’t know which number your doctor provided, ask for clarification.
What the Numbers Mean
Survival rates are read as the percentage of people who lived beyond five years after being diagnosed with colon cancer. For instance, the five-year relative survival rate for localized colon cancer is 90.1 percent. This means that 90.1 percent of the people diagnosed with localized colon cancer were still alive at the conclusion of the study.
How Survival Rates are Used
Although you or your loved ones may use the survival rates as an indication of "how bad the cancer is," the doctors use these numbers for a different reason. Paired with your stage at being diagnosed with colon cancer, age, ethnicity and gender, these numbers provide the doctor with more information on how to best treat your colon cancer.
Survival rates are also used for statistical trending, so that future generations may benefit from tracking colon cancer and learn more about outcomes based on stage and treatment modalities. Looking back, the relative survival rate for colon cancer was less than 50 percent in 1975 and climbed to 64.1 percent between 1995 and 2001, according to the American Cancer Society. Moving forward, the rate increased to 64.3 percent between 2001 and 2007, according to the National Cancer Institute (NCI).
The increase in relative survival rate is largely reflective of the improvements in understanding, preventing and treating colon cancer. Every decade, new treatments become available, which will hopefully continue to reflect in increasing survival rates for people with colon cancer.
Survival Rates by Stage
Supplied by the National Cancer Institute SEER survey, these colon cancer survival statistics are from data collected in 2007. The five-year relative survival rate for each stage of cancer is:
- Localized -- 90.1 percent
- Regional – 69.2 percent
- Distant – 11.7 percent
- Unknown – 33.3 percent
Localized colon cancer statistics include stages 0 and I. When the cancer was diagnosed, it had not spread through the bowel wall and there was no metastatic disease. This survival rate has increased from 90 percent in 2000, according to the NCI.
Regional colon cancer statistics include stages II, IIA and IIIC, however there is a large fluctuation between stage II survival rates and stage IIIC. When the cancer was diagnosed, it had spread past the bowel wall and possibly into local (regional) lymph nodes. As opposed to the current 69.2 survival rate, the regional survival rate used to be 67 percent as of 2000 per the NCI.
Distant colon cancer statistics include stage IV. The disease has metastasized (spread) throughout the body and distant tumors are present. Although the current survival rate is 11.7 percent for distant colon cancer, this number used to be only 10 percent as of 2000 according to the NCI.
The unknown category includes anyone who had colon cancer that was not staged.
Another point to remember about these numbers: They are outdated the minute they hit the press. Organizations such as the National Cancer Institute are gathering the current colon cancer statistics as you read this, but those numbers won’t be compiled for years. At the very least, the data collected will always be five years behind (five-year survival rate needs at least five years of data collection). By the time the next survival rate statistics are reported, there is a chance that the suggested chemotherapy, surgery or even radiation therapies for colon cancer may have improved, or at least changed.
American Cancer Society. (2006). American Cancer Society’s Complete Guide to Colorectal Cancer. Clifton Fields, NE: American Cancer Society.
National Cancer Institute. (November, 2011). Cancer of the Colon and Rectum: SEER Stat Fact Sheets. Accessed February 19, 2012.
National Cancer Institute. (n.d.). SEER Fast Stats: 5 Year Relative Survival by Year Diagnosed 1975 – 2003. Accessed February 21, 2012.