Formerly known as Duke C colon cancer, stage 3 is a stage where the tumor has spread beyond its original site in the mucosa, or the first layer of the colon, into the serosa, the outermost layer. There, the tumor breeds while waiting to travel into a lymph node or blood vessel that will transport it to distant body parts.

Differentiating 3A, 3B and 3C

Stage 3 colon cancer is divided into three groups, from least advanced to most advance. The earliest stage is known as Stage 3A (formerly Duke C1), the middle stage is Stage 3B (Duke C2) and the most advanced stage is Stage 3C (Duke C3).

Stage 4 colon cancer is the most advanced colon cancer stage. The stage of a cancer, usually 1 to 4, indicates how much the disease has spread. It often takes into account the size of the tumor, how deep it has penetrated, whether it has invaded nearby organs, if and how many lymph nodes it has metastasized to, and whether it has reached distant organs.

The staging of cancer is essential because the stage during diagnosis is the strongest predictor of survival. Additionally, recommended treatments are often changed based on the cancer stage. Generally, the earlier the stage, the easier the cancer is to treat. There are five stages of colon cancer, from stages 0 to 4.