FIGO System & TNM System to Stage Ovarian Cancer

Ovarian cancer staging usually is described in terms of the FIGO system (staging scheme developed by the International Federation of Gynecology and Obstetrics) and the TNM system (classification system developed by the American Joint Committee on Cancer [AJCC]). Ovarian cancer treatment ultimately depends upon such staging. In general, the lower the stage, the more favorable is the prognosis.

According to the TNM system:
T = Tumor Size
N = Node Involvement
M = Metastasis status

Tumors
The primary tumor (T) is classified according to the following categories:

  • T1: Tumor is limited to one or both ovaries.
    • T1a: Tumor is limited to one ovary. The capsule, or outer wall of the tumor, is intact, there is no tumor on the ovarian surface, and there are no cancer cells in ascites (abdominal fluid build-up) or peritoneal lavage ("washings" from the abdominal cavity).
    • T1b: Tumor is limited to both ovaries. The capsule is intact, there is no tumor on the ovarian surface, and there are no cancer cells in ascites or peritoneal lavage.
    • T1c: Tumor is limited to one or both ovaries with any of the following: ruptured capsule (burst outer wall of the tumor), tumor on ovarian surface, or cancer cells in the ascites or peritoneal lavage.
  • T2: Tumor involves one or both ovaries with spread into the pelvis.
    • T2a: Tumor has spread and/or attaches to the uterus and/or fallopian tubes. There are no cancer cells in ascites or peritoneal lavage.
    • T2b: Tumor has spread to other pelvic tissues. There are no cancer cells in ascites or peritoneal lavage.
    • T2c: Tumor has spread to pelvic tissues, with cancer cells in ascites or peritoneal lavage.
  • T3: Tumor involves one or both ovaries, with microscopically confirmed peritoneal metastasis outside the pelvis and/or metastasis to regional (nearby) lymph node(s).
    • T3a: Microscopic peritoneal metastasis beyond the pelvis.
    • T3b: Macroscopic (visible to the naked eye) peritoneal metastasis beyond the pelvis, 2 cm or less in greatest dimension.
    • T3c: Peritoneal metastasis beyond the pelvis, more than 2 cm in greatest dimension.

Nodes
The regional lymph nodes (N) are clinically divided into the following categories:

  • N0: Regional lymph nodes contain no metastases.
  • N1: Evidence of lymph node metastasis.

Metastasis
The state of metastasis (M) is defined as follows:

  • M0: No distant metastases are found (this excludes peritoneal metastasis).
  • M1: Distant metastases are present.

Stage Grouping

The TNM system places ovarian cancer growth at a particular stage. There are four basic stage groupings within the TNM system:

  • Stage 1
    • Stage Ia: T1a, N0, M0
    • Stage Ib: T1b, N0, M0
    • Stage Ic: T1c, N0, M0
  • Stage 2
    • Stage IIa: T2a, N0, M0
    • Stage IIb: T2b, N0, M0
    • Stage IIc: T2c, N0, M0
  • Stage 3
    • Stage IIIa: T3a, N0, M0
    • Stage IIIb: T3b, N0, M0
    • Stage IIIc: T3c, N0, M0, or T(any), N1, M0
  • Stage 4: T(any), N(any), M1

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 14 Aug 1999

Last Modified: 29 Sep 2015