Appendix Cancer Staging

If a biopsy confirms the presence of appendix cancer, your doctor will need to know the stage (extent) of the disease to plan the best treatment. Staging appendix cancer is challenging because of the different tumor types, which all have unique features that affect treatment options and prognosis.

Appendiceal neuroendocrine tumors and appendiceal adenocarcinomas are both staged using the TNM staging system, which is based on three key pieces of information:

• T: The size of the tumor in the appendix
• N: Whether the tumor has invaded nearby lymph nodes
• M: Whether the cancer has spread (metastasized), and if so, to what parts of the body

Once the T, N, and M categories of the cancer have been determined, this information is combined to assign an overall stage. The stages of appendix cancer range from 0 to IV, with higher numbers indicating the cancer has become more advanced. 

Stages of appendiceal neuroendocrine tumors (carcinoid)

Stage I: Tumor is 2 cm wide or smaller and has not spread to any lymph nodes.

Stage II: Tumor is larger than 2 cm and may or may not be growing in other layers of tissue around the appendix. It has not spread to lymph nodes or distant parts of the body.

Stage III: Tumor has not metastasized to distant parts of the body but may have spread to nearby lymph nodes. Or it may be growing in the outermost tissue layer of the appendix (the peritoneum) or nearby structures or organs.

Stage IV: The cancer has spread to distant parts of the body.

Additionally, appendiceal neuroendocrine tumors are staged based on whether they can be completely removed surgically and how the cells look under a microscope (known as cancer grade). The higher the grade, the more abnormal the cells look. Low-grade tumors typically have a better prognosis as they can often be removed with surgery.

Stages of appendiceal carcinomas

Stage 0: Cancer is found in only one place and has not spread. Stage 0 is referred to as cancer in situ (Latin for ‘in place’).

Stage I: Tumor has spread to the inner layers of appendix tissue but not to regional lymph nodes or other parts of the body.

Stage IIA: Tumor has spread to the connective or fatty tissue next to the appendix but not to the regional lymph nodes or other parts of the body.

Stage IIB: Tumor has grown through the lining of the appendix but has not spread to the regional lymph nodes or other parts of the body.

Stage IIC: Tumor has invaded other organs, such as the colon or rectum, but has not spread to the regional lymph nodes or other parts of the body.

Stage IIIA: Tumor has spread to the inner layers of the appendix tissue and is affecting one to three regional lymph nodes, but has not spread to other areas of the body.

Stage IIIB: Tumor has reached nearby tissues of the appendix or spread through the lining of the appendix. It has reached one to three regional lymph nodes but has not spread to other areas of the body.

Stage IIIC: Tumor has spread to four or more regional lymph nodes but has not spread to other areas of the body.

Stage IVA: Tumor has spread to other areas in the abdomen but not to the regional lymph nodes. The cancer cells are well-differentiated.

Stage IVB: Tumor has spread to other areas in the abdomen and possibly to regional lymph nodes. These cancer cells are moderately or poorly differentiated.

Stage IVC: Tumor has spread outside the abdominal area to distant parts of the body, such as the lungs.