Stages of Appendiceal Cancer

If a tumor is found, your doctor will determine its stage by judging its size and how far it has progressed. The cancer can be localized (which means it has not spread outside of the appendix), regional (spread to lymph nodes, tiny bean-shaped organs that help the body fight infections), and metastatic (spread to other parts of the body). Carcinoid tumors and carcinomas are staged differently.

Staging for carcinoid tumors of the appendix

Oncologists use a staging system referred to by its abbreviation, TNM, to be as detailed about the tumor as possible.

T refers to the tumor itself, where it is, and how large it is.

  • T1: The tumor is no more than 2 cm (about fourth-fifths of an inch) across.
  • T2: The tumor is larger than 2 cm across but not larger than 4 cm or has grown into the cecum (the first part of the large intestine).
  • T3: The tumor is larger than 4 cm across or has grown into the ileum (the last part of the small intestine).
  • T4: The tumor has grown into nearby organs or tissues, such as the abdominal wall.

N refers to the lymph nodes, whether the cancer has spread to them, and if so, how many nodes are affected.

  • NX: Nearby (regional) lymph nodes cannot be assessed.
  • N0: The cancer has not spread to nearby lymph nodes.
  • N1: The cancer has spread to nearby lymph nodes.

M refers to whether the cancer has metastasized (spread), and if so, to what parts of the body.

  • M0: The cancer has not metastasized to distant organs or structures.
  • M1: The cancer has metastasized to distant organs or structures, such as the liver or peritoneum.

Doctors may also refer to stages, from stage I through IV, to describe carcinoid cancer of the appendix.

Staging for carcinomas of the appendix

T refers to the tumor itself, where it is, and how large it is.

  • TX: The primary tumor cannot be evaluated.
  • T0: There is no evidence of cancer in the appendix.
  • Tis: This refers to carcinoma in situ (also called cancer in situ). Cancer cells are found only in the first layers lining the inside of the appendix.
  • T1: The tumor has invaded the submucosa, which is the next deepest layer of the appendix.
  • T2: The tumor has invaded the muscularis propria, which is the third layer of the appendix.
  • T3: The tumor has grown through the muscularis propria and into the subserosa (a thin layer of connective tissue) of the appendix or into the mesoappendix, which is an area of fatty tissue next to the appendix that provides its blood supply.
  • T4: The tumor has grown through the visceral peritoneum (the lining of the abdominal cavity) or invaded other organs.
  • T4a: The tumor has invaded the visceral peritoneum.
  • T4b: The tumor has invaded other organs or structures, such as the colon or rectum.

N refers to the lymph nodes, whether the cancer has spread to them, and if so, how many nodes are affected.

  • NX: The regional lymph nodes cannot be evaluated because of a lack of information.
  • N0: There is no regional lymph node metastasis.
  • N1: Cancer has spread to one to three regional lymph nodes.
  • N2: Cancer has spread to four or more regional lymph nodes.

M refers to whether the cancer has metastasized (spread), and if so, to what parts of the body.

  • MX: Distant metastasis cannot be evaluated.
  • M0: The cancer has not metastasized.
  • M1a: There is intraperitoneal metastasis, which means the cancer has spread to organs or structures within the abdominal area.
  • M1b: There is nonperitoneal distant metastasis, which means the cancer has spread outside of the abdominal cavity.

Doctors also characterize carcinomas of the appendix by their grade (G), which describes how much cancer cells look like healthy cells when viewed under a microscope.

Healthy tissue usually contains many different types of cells grouped together. If the cancer looks similar to healthy tissue and contains different cell groupings, it is called differentiated or a low-grade tumor. If the cancerous tissue looks very different from healthy tissue, it is called poorly differentiated or a high-grade tumor. The cancer’s grade is one of the most important factors in metastatic appendix carcinoma and helps predict how quickly the cancer will spread. In general, the lower the tumor’s grade, the better the prognosis.

  • GX: The tumor grade cannot be identified.
  • G1: The tumor cells are well differentiated.
  • G2: The tumor cells are moderately differentiated.
  • G3: The tumor cells are poorly differentiated.
  • G4: The tumor cells are undifferentiated.

Your doctors may also refer to stages, from stage I through IV, to describe your cancer, by combining the T, N, M, and G classifications.

Stage 0

Stage 0 refers to cancer in situ. The cancer is found in only one place and has not spread.

Stage I

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

Stage II

Stage II is divided into three subcategories:

  • Stage IIA means the cancer has grown into the connective or fatty tissue next to the appendix but has not spread to the regional lymph nodes or to other parts of the body.
  • Stage IIB means the cancer has grown through the lining of the appendix but has not spread to the regional lymph nodes or to other parts of the body.
  • Stage IIC means the tumor has grown into other organs, such as the colon or rectum, but has not spread to the regional lymph nodes or to other parts of the body.

Stage III

Stage III is also divided into three subcategories:

  • Stage IIIA means the cancer has spread to inner layers of appendix tissue and to one to three regional lymph nodes but has not spread to other parts of the body.
  • Stage IIIB means the cancer has grown into nearby tissue of the appendix or through the lining of the appendix and to one to three regional lymph nodes but has not spread to other areas of the body.
  • Stage IIIC describes a cancer that has spread to four or more regional lymph nodes but not to other areas of the body.

Stage IV

Stage IV is also divided into three subcategories:

  • Stage IVA describes a cancer that has spread to other areas in the abdomen but not to the regional lymph nodes; the cancer cells are well differentiated.
  • Stage IVB means:
    • The cancer has spread to other areas in the abdomen but not to the regional lymph nodes, and the cells are moderately or poorly differentiated.
    • The cancer has spread to other areas in the abdomen and to one to three regional lymph nodes, and the cells may be any grade.
    • The cancer has spread to other areas in the abdomen and to four or more regional lymph nodes, and the cells may be any grade.
  • Stage IVC: The cancer has spread outside the abdominal area to distant parts of the body, such as the lungs.