Human Ovarian Cancer

Tumor Classification and Staging

Ovarian cancer treatment ultimately depends upon careful staging. In general, the lower the stage, the more favorable is the individual's prognosis. Both International Federation of Gynecology and Obstetrics (FIGO) staging19 and tumor/node/metastasis (TNM) staging are commonly used in the determination of ovarian cancer stage (Tables 1-6). The TNM system is a classification system developed by the American Joint Committee on Cancer (AJCC).²⁰

Table 1. TNM Staging-Tumors²⁰

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.

Table 2. TNM Staging-Nodes²⁰

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

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

Table 3. TNM Staging-Metastasis²⁰

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

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

Table 4. TNM Staging-Stage Grouping ²⁰

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

Stage 1a:	T1a, N0, M0
Stage 1b:	T1b, N0, M0
Stage 1c:	T1c, N0, M0
Stage 2a:	T2a, N0, M0
Stage 2b:	T2b, N0, M0
Stage 2c:	T2c, N0, M0
Stage 3a:	T3a, N0, M0
Stage 3b:	T3b, N0, M0
Stage 3c:	T3c, N0, M0 or T(any), N1, M0
Stage 4:	T(any), N(any), M1

Table 5. FIGO Staging¹⁹

Stage I	Growth limited to the ovaries
	Ia Growth limited to one ovary; no ascites present containing malignant cells. No tumor on the external surface; capsule intact
	Ib Growth limited to both ovaries; no ascites present containing malignant cells. No tumor on the external surfaces; capsules intact
	Ica Tumor either Stage Ia or Ib, but with tumor on surface of one or both ovaries, or with capsule ruptured, or with ascites present containing malignant cells, or with positive peritoneal washings
Stage II	Growth involving one or both ovaries with pelvic extension
	IIa Extension and/or metastases to the uterus and/or tubes
	IIb Extension to other pelvic tissues
	IIca Tumor either Stage IIa or IIb, but with tumor on surface of one or both ovaries; or with capsule(s) ruptured; or with ascites present containing malignant cells or with positive peritoneal washings
Stage III	Tumor involving one or both ovaries with histologically confirmed peritoneal implants outside the pelvis and/or positive retroperitoneal or inguinal nodes. Superficial liver metastases equals Stage III. Tumor is limited to the true pelvis, but with histologically proven malignant extension to small bowel or omentum
	IIIa Tumor grossly limited to the true pelvis, with negative nodes, but with histologically confirmed microscopic seeding of abdominal peritoneal surfaces, or histologic-proven extension to small bowel or mesentery
	IIIb Tumor of one or both ovaries with histologically confirmed implants, peritoneal metastasis of abdominal peritoneal surfaces, none exceeding 2 cm in diameter; nodes are negative
	IIIc Peritoneal metastasis beyond the pelvis > 2 cm in diameter and/or positive retroperitoneal or inguinal nodes
Stage IV	Growth involving one or both ovaries with distant metastases. If pleural effusion is present, there must be positive cytology to allot a case to Stage IV. Parenchymal liver metastasis equals Stage IV

^aIn order to evaluate the impact on prognosis of the different criteria for allotting cases to Stage Ic or Iic, it would be of value to know if rupture of the capsule was spontaneous, or caused by the surgeon; and if the source of malignant cells detected was peritoneal washings, or ascites.