Ovarian Cancer

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Early Detection, Diagnosis, and Staging TOPICS

How is ovarian cancer staged?

Staging is the process of finding out how widespread a cancer is. Most ovarian cancers that are not obviously widespread are staged at surgery. One of the goals of surgery for ovarian cancer is to take tissue samples for diagnosis and staging. To stage the cancer, samples of tissues are taken from different parts of the pelvis and abdomen and examined under the microscope.

Staging is very important because ovarian cancers have different prognoses at different stages and are treated differently. The accuracy of the staging may determine whether or not a patient will be cured. If the cancer isn’t accurately staged, then cancer that has spread outside the ovary might be missed and not treated. Once a stage has been given it does not change, even when the cancer comes back or spreads to new locations in the body.

Ask your cancer care team to explain the staging procedure. After surgery, ask what your cancer's stage is. In this way, you will be able to make informed decisions about your treatment. One of the reasons it is important to be operated on by a gynecologic oncologist is that you are more likely to be staged accurately.

Ovarian cancer can be staged according to the AJCC/TNM System. This describes the extent of the primary tumor (T), the absence or presence of metastasis to nearby lymph nodes (N), and the absence or presence of distant metastasis (M). This closely resembles the system that is actually used by most gynecologic oncologists, called the FIGO system. Both rely on the results of surgery for the actual stages. Fallopian tube cancer is staged like ovarian cancer, but with different T categories. Primary peritoneal cancer (PPC) is staged like ovarian cancer, with all cases being either stage III or IV depending on whether the cancer has spread to distant sites.

T categories for ovarian cancer

Tx: No description of the tumor's extent is possible because information is incomplete.

T1: The cancer is confined to one or both ovaries.

  • T1a: The cancer is only inside one ovary − it isn’t on the outside of the ovary, it doesn’t penetrate the tissue covering the ovary (called the capsule) and isn’t in fluid taken from the pelvis.
  • T1b: The cancer is inside both ovaries but doesn't penetrate to the outside and isn’t in fluid taken from the pelvis (like T1a except the cancer is in both ovaries).
  • T1c: The cancer is in one or both ovaries and is either on the outside of an ovary, grown through the capsule of an ovary, or is in fluid taken from the pelvis.

T2: The cancer is in one or both ovaries and is extending into pelvic tissues.

  • T2a: The cancer has metastasized (spread) to the uterus and/or the fallopian tubes but isn’t in fluid taken from the pelvis.
  • T2b: The cancer has spread to pelvic tissues besides the uterus and fallopian tubes but it isn’t in fluid taken from the pelvis.
  • T2c: The cancer has spread to the uterus and/or fallopian tubes and/or other pelvic tissues (like T2a or T2b) and is also in fluid taken from the pelvis.

T3: The cancer is in one or both ovaries and has spread to the abdominal lining outside the pelvis. This lining is called the peritoneum.

  • T3a: The cancer metastases are so small that they cannot be seen except under a microscope.
  • T3b: The cancer metastases can be seen but no tumor is bigger than 2 centimeters (0.8 inches).
  • T3c: The cancer metastases are larger than 2 centimeters (0.8 inches).

T categories for fallopian tube cancer

Tx: No description of the tumor's extent is possible because information is incomplete.

Tis: Cancer cells are only in the inner lining of the fallopian tube. They haven’t grown into deeper layers. Also called carcinoma in situ.

T1: The cancer is in the fallopian tube(s), but has not grown outside of them.

  • T1a: The cancer is only inside one fallopian tube − it has not grown through to the outside of the tube. It hasn't grown through the tissue covering the tumor (called the capsule) and isn’t in fluid taken from the pelvis.
  • T1b: The cancer is growing in both fallopian tubes − it has not grown through to the outside of the tube. It hasn't grown through the tissue covering the tumor (called the capsule) and isn’t in fluid taken from the pelvis (like T1a but with tumor in both tubes).
  • T1c: The tumor is in one or both fallopian tubes and has either grown through the outer wall of the tube or cancer cells are found in fluid taken from the pelvis.

T2: The tumor has grown from one or both fallopian tubes into the pelvis.

  • T2a: The cancer is growing into the uterus and/or the ovaries.
  • T2b: The cancer is growing into other parts of the pelvis.
  • T2c: The cancer has spread from the fallopian tubes into other parts of the pelvis and cancer cells are found in fluid taken from the pelvis (either from ascites or from washings obtained at surgery.

T3: The tumor has spread outside the pelvis to the lining of the abdomen.

  • T3a: The areas of cancer spread outside the pelvis can only be found when the area is biopsied and looked at under the microscope.
  • T3b: The areas of spread can be seen with the naked eye, but are 2 cm or less in size (less than an inch).
  • T3c: The areas of spread are greater than 2 cm in size.

N categories

N categories indicate if the cancer has spread to regional (nearby) lymph nodes.

Nx: No description of lymph node involvement is possible because information is incomplete.

N0: No lymph node involvement.

N1: Cancer cells are found in the lymph nodes close to tumor.

M categories

M categories indicate if the cancer has spread to distant organs, such as the liver, lungs, or non-regional lymph nodes.

M0: No distant spread.

M1: Cancer has spread to the inside of the liver, to the lungs, or other organs.

Stage grouping

Once a patient's T, N, and M categories have been determined, this information is combined in a process called stage grouping to determine the stage, expressed in Roman numerals from stage I (the least advanced stage) to stage IV (the most advanced stage). The following table illustrates how TNM categories are grouped together into stages. These stages are the same as the FIGO stages. This stage grouping also applies to fallopian tube carcinoma.

What the stages of ovarian cancer mean

Stage I

The cancer is still contained within the ovary (or ovaries). It has not spread outside the ovary.

Stage IA (T1a, N0, M0): Cancer has developed in one ovary, and the tumor is confined to the inside of the ovary. There is no cancer on the outer surface of the ovary. Laboratory examination of washings from the abdomen and pelvis did not find any cancer cells.

Stage IB (T1b, N0, M0): Cancer has developed in both ovaries but not on their outer surfaces. Laboratory examination of washings from the abdomen and pelvis did not find any cancer cells.

Stage IC (T1c, N0, M0): The cancer is present in one or both ovaries and one or more of the following are present:

  • Cancer is on the outer surface of at least one of the ovaries.
  • In the case of cystic tumors (fluid-filled tumors), the capsule (outer wall of the tumor) has ruptured (burst)
  • Laboratory examination found cancer cells in fluid or washings from the abdomen.

Stage II

The cancer is in one or both ovaries and has spread to other organs (such as the uterus, fallopian tubes, bladder, the sigmoid colon, or the rectum) within the pelvis. It has not spread to lymph nodes, the lining of the abdomen (called the peritoneum), or distant sites.

Stage IIA (T2a, N0, M0): The cancer has spread to or has invaded (grown into) the uterus or the fallopian tubes, or both. Laboratory examination of washings from the abdomen did not find any cancer cells.

Stage IIB (T2b, N0, M0): The cancer has spread to other nearby pelvic organs such as the bladder, the sigmoid colon, or the rectum. Laboratory examination of fluid from the abdomen did not find any cancer cells.

Stage IIC (T2c, N0, M0): The cancer has spread to pelvic organs as in stages IIA or IIB and cancer cells were found when the fluid from the washings from the abdomen were examined under a microscope.

Stage III

The cancer is in one or both ovaries, and one or both of the following are present: (1) cancer has spread beyond the pelvis to the lining of the abdomen; (2) cancer has spread to lymph nodes.

Stage IIIA (T3a, N0, M0): During the staging operation, the surgeon may be able to see cancer in the ovary or ovaries, but no cancer is visible to the naked eye in the abdomen and the cancer has not spread to lymph nodes. However, when biopsies are checked under a microscope, tiny deposits of cancer are found in the lining of the upper abdomen.

Stage IIIB (T3b, N0, M0): There is cancer in one or both ovaries, and deposits of cancer large enough for the surgeon to see, but smaller than 2 cm (about 3/4 inch) across, are in the abdomen. Cancer has not spread to the lymph nodes.

Stage IIIC: The cancer is in one or both ovaries, and one or both of the following are present:

  • Cancer has spread to lymph nodes (any T, N1, M0)
  • Deposits of cancer larger than 2 cm (about 3/4 inch) across are seen in the abdomen (T3c, N0, M0).

Stage IV (any T, any N, M1)

This is the most advanced stage of ovarian cancer. In this stage the cancer has spread to the inside of the liver, the lungs, or other organs located outside the peritoneal cavity. (The peritoneal cavity, or abdominal cavity is the area enclosed by the peritoneum, a. membrane that lines the inner abdomen and covers most of its organs.) Finding ovarian cancer cells in the fluid around the lungs (called pleural fluid) is also evidence of stage IV disease.

Recurrent ovarian cancer: This means that the disease went away with treatment but then came back (recurred).


Last Medical Review: 03/21/2013
Last Revised: 02/06/2014