|SEER Stage||Percentage Diagnosed||Five-Year Survival Rate|
Survival Rate by Cancer Type
The majority of colon cancers involve a type of cancer known as adenocarcinoma, which originates in glands and glandular tissues. There are other less common types, some of which are more aggressive and harder to treat.
Adenocarcinoma accounts for around 95% of all colorectal cancers. Although SEER statistics are based largely on this type of cancer, there are rare subtypes known as mucinous adenocarcinoma and signet-ring cell carcinoma that are far more aggressive.
Mucinous adenocarcinoma originates in mucus-producing glands of the colon. Because the mucus can facilitate the spread of cancer cells, mucinous adenocarcinoma tends to be more invasive. Compared to typical adenocarcinoma, mucinous adenocarcinoma is associated with no less than a 20% reduction in overall survival times.
Signet-ring cell carcinoma accounts for less than 1% of colon cancers and is differentiated by the appearance of its cells. This rare form of adenocarcinoma tends to be extremely aggressive, reflected by an overall five-year survival rate of 36.3%—roughly half of what is expected with typical adenocarcinoma.
GIST originates in a specific type of cell called an interstitial cell and can either be malignant or benign. Of the 30% that are malignant, the majority occur either in the stomach, small intestine, or rectum.
GIST is associated with generally poorer outcomes, with an overall five-year survival rate of 46%.
Leiomyosarcoma is a type of cancer affecting smooth muscles, including those of the colon and rectum. They are extremely rare, accounting for less than 0.1% of all colon cancers, and have an overall five-year survival rate of 43.8%.
Primary colorectal lymphoma is a type of non-Hodgkin lymphoma (NHL) affecting a type of white blood cell called a lymphocyte. Unlike Hodgkin lymphoma (HL), which typically progresses in an orderly fashion through the lymphatic system, NHL can develop in any part of the body, including the colon.
Primary colorectal lymphomas account for just 0.5% of all colorectal cancers and around 5% of all lymphomas. With that said, they tend to be associated with poorer outcomes, in part because they are difficult to diagnose. Studies suggest that the overall five-year survival rate for primary colorectal lymphoma is 56.4%.
Melanoma is predominately known as a type of skin cancer but can affect any cell that produces the pigment known as melanin. These melanocytes can be found in the gastrointestinal tract and, in rare instances, can lead to primary colorectal melanoma.
Primary colorectal melanoma accounts for around 1% of all colorectal cancers and has by far the worst outcomes, with an overall five-year survival rate of just 20%.
Factors That Influence Survival
The SEER survival estimates only paint a general picture of what to expect if you have colon cancer. Because the estimates are based on everyone with colon cancer, the statistics may not accurately reflect what is ahead for you as an individual.
There are several factors that influence survival times. Some are non-modifiable, meaning that you cannot change them, while others are modifiable and may potentially influence outcomes.
The surgical removal of the primary tumor, known as a resection, can increase the odds of remission and reduce the likelihood of disease progression. While surgery remains a primary form of colon cancer treatment, it is not appropriate for everyone.
Some cancers are inoperable and cannot be removed because of their location and/or the general health of the patient. Similarly, advanced metastatic cancers are rarely treated with resection because the procedure is not seen to improve survival times in most people.
When surgery is indicated, the resection of the primary tumor can increase the overall five-year survival rate to 73.8% while reducing the risk of recurrence to just 6.4%.
In people with inoperable colon cancer, a minimally invasive approach called stereotactic radiation therapy (SBRT) offers a viable alternative to surgery. Studies suggest that people who undergo SBRT for stage 4 colorectal cancer have a four-year survival rate of around 43% when accompanied by chemotherapy.
Your age at the time of the colon cancer diagnosis can influence survival times as it can with other diseases. With a median age of diagnosis of 68 in men and 72 in women, older age already plays a central role in the onset of the disease. However, with each subsequent year, the risk of mortality increases.
According to a 2015 study in the Journal of Gastrointestinal Oncology, the overall five-year survival rate for people over 63 was 58.8%, dropping to 40.8% in those over 79—a drop of nearly 30%.
While age clearly plays a role in cancer survival times, not all older people are at equal risk. A person’s performance status (PS)—the ability to take care of oneself and perform everyday activities—also factors in.
PS is measured in several different ways. Chief among them is the Eastern Cooperative Oncology Group (ECOG) system, which classifies PS on a score of 0 (fully active) to 4 (fully disabled). Having a lower score generally means that you are less able to tolerate cancer treatments.
According to a 2017 study from Cleveland Clinic, a low, intermediate, and high PS score translates to a mortality rate of 8.1%, 11.2%, and 32.5%, respectively, within six months of the diagnosis.
The researchers further concluded that PS plays a more central role in survival times than either age or co-occurring medical conditions.
Race plays a central, albeit indirect, role in cancer survival rates due mainly to the lack of access to quality healthcare. This is a narrative that not only affects people with colon cancer but all other health conditions as well.
In the United States, the overall five-year survival rate for Whites with colon cancer is 65.4%. By contrast, Blacks have a five-year survival rate of 54.7%—a reduction of nearly 9%.
Contributing to this statistic is the higher rate of stage 4 colon cancer among Blacks, who are 20% more likely to be diagnosed after the tumor has metastasized compared to Whites.
Weight plays a role in the onset and progression of colon cancer as it does with many other diseases. Being overweight or obese not only contributes to the risk of the disease but can also influence outcomes after the tumor has been treated. This is especially true in women.
According to a 2013 study in the British Journal of Cancer, overweight and obese women have almost twice the risk of dying from colon cancer compared with women of normal weight.
Although the cause of this is poorly understood, having a high body mass index (BMI) increases the risk of insulin resistance, chronic inflammation, and impaired hormone function. Each of these is independently linked to both the onset and progression of colon cancer.
Routine exercise may improve colon cancer survival, with some studies reporting anywhere from a 40% to 70% reduction in post-treatment mortality compared to people who engage in no exercise.
Smoking affects all cancers, and colon cancer is no exception. Cigarette smoke not only induces chronic inflammation but also causes oxidative damage to DNA. These factors not only contribute to the onset of the disease but appear to increase the risk of colon cancer recurrence.
A 2015 review in the Annals of Oncology found that smoking after a colon cancer diagnosis increases the 60-day risk of death by 49% or more compared to never-smokers.
Not surprisingly, smoking cessation was linked to a 78% improvement in survival times compared to people who did not quit.
A Word From Verywell
It can be distressing to be diagnosed with colon cancer and even more distressing to be faced with the survival statistics. Whatever the stage of your cancer, it is important to remember that the statistics are based on everyone with the disease, regardless of their age, health, and other risk factors.
Many people live well beyond their initial prognosis. With newer, improved diagnostics and treatments, those gains are likely to increase. So, rather than focusing on survival times, focus on the factors you can change and keep appraised of the latest treatments and treatment approaches.
By working with your oncologist and become an “expert” on your disease, you are more likely to reap the benefits of treatment by making informed choices.