Colorectal Cancer Stages

Nobody wants to hear the words, “It’s stage four cancer.” These diagnoses are often difficult to cope with and can elicit feelings of hopelessness in both cancer patients, their caregivers and loved ones.

Cancer is known to many as a severe illness and a leading cause of death around the world. However, it is possible to recover from cancer with the help of early detection and diagnosis. In most cases, the sooner the cancer is detected and treated, the better the chances of recovery and survival.

That being said, successful treatment also depends on many factors, such as:

• The severity of the cancer when it is detected and diagnosed
• How aggressively it develops

Different stages are used to describe how much cancer has grown or spread. Identifying the correct cancer stage helps doctors assess how severe the cancer is and administer the appropriate treatment.

Like many other cancers, colorectal cancer can be broadly classified from stage I (1) to stage IV (4). Each stage indicates a different severity based on the size of the growth, and if it has spread to other parts of the body.

Each cancer stage (and sub-stage) is determined based on the American Joint Committee on Cancer (AJCC) TNM system. Specifically, the TNM system takes the following into account:

• The size and extent of the primary tumor (T). Most colorectal cancers begin in the lining of the large intestine. The T grading assesses if the cancer has grown into and penetrated the wall of the large intestine.
• The cancer’s spread to the nearby lymph nodes (N) located along the colon.
• The cancer’s spread to other parts of the body through metastasis (M). This takes into account the cancer’s spread to distant lymph nodes and organs such as the lungs or liver.

Different colorectal cancer stages are determined based on the TNM system.

The flowchart below details how each T, N and M grading is derived.

Click 'Present' and tap on the right arrow button (>) to start navigating through the grading process.

Broadly speaking, stage 1 and 2 colorectal cancer is characterized by two things:

• The presence of cancerous growth in the colon’s walls, and
• The absence in nearby lymph nodes and other distant organs

Simply put, the cancer has yet to spread to lymph nodes, which also indicates that spread to other distant organs is less likely. Surgery alone is often curative for these stages of colorectal cancer. However, the cancer may recur as metastatic disease, especially in high-risk stage 2 colorectal cancers.

Stage 3 colorectal cancer can be identified by tumors that have grown significantly in the intestinal wall and spread to the nearby lymph nodes. In more severe substages, the tumor may even spread through the intestinal wall and to several regional lymph nodes.

Stage 4 is when the cancer is more advanced and has spread to other distant organs such as the lungs or liver. This ability to colonize distant organs is a key difference between stage 3 and 4 cancer.

Metastasis to other organs often means that treatment becomes more complicated and may not be curative. Nonetheless, there are exceptions. For instance, metastasis to the liver that is limited to one spot is more easily treated with surgery.

A more complete breakdown of each stage and the TNM combination is given below.

Based on the different stages, there are many different ways to get a specific cancer stage diagnosis. However, staging alone does not account for how aggressive or quickly it may grow and spread. This requires further investigation through laboratory tests of biopsied tumor samples.

Most importantly, it is difficult to predict outcomes in any individual person. Some people with “high risk” genetic mutations in the cancer or other features can still do quite well if their cancer responds to treatment.

Being aware of the symptoms of colorectal cancer and detecting the cancer early through regular screening tests can make a difference how successful the treatment is. Particularly for those aged 45 and above, regular screening is recommended as a preventive measure. This proactive approach will positively affect one's healthcare, underscoring the vital significance of health screenings and check-ups.