How many levels are identified in the T staging of colon cancer?

The T staging of colon cancer is divided into four levels, which describe the extent of tumor invasion into the layers of the bowel wall as well as the surrounding tissues.

• T1 indicates that the tumor has invaded through the mucosa and into the submucosa.

• T2 means the tumor has penetrated through the muscularis propria, but not beyond it.

• T3 indicates that the tumor has grown into the subserosa or the pericolic/perirectal tissues.

• T4 represents a further advance, which can be subdivided into T4a, where there is invasion of the serosa (visceral peritoneum) or T4b, where the tumor invades other organs or structures.

These levels help determine the prognosis and guide treatment decisions for patients with colon cancer. By classifying the tumors into these four categories, healthcare providers can better understand how extensive the disease is, which is critical for planning surgical approaches and adjunct therapies.