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 the time of surgery. One of the goals of surgery for ovarian cancer is to obtain tissue samples for diagnosis and staging. In order 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 a different prognosis 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 is not properly staged, then cancer that has spread outside the ovary may 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. Also ask them if they will perform a thorough staging procedure. After surgery, ask what your cancer's stage is. In this way, you will be able to take part in making informed decisions about your treatment.
Ovarian cancer is 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 of incomplete information.
T1: The cancer is confined to the ovaries -- one or both.
T1a: The cancer is only inside one ovary - it is not on the outside of the ovary, it doesn’t penetrate the tissue covering the ovary (called the capsule) and is not in fluid taken from the pelvis.
T1b: The cancer is inside both ovaries but doesn't penetrate to the outside and is not 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 spread (metastasized) to the uterus and/or the fallopian tubes but is not in fluid taken from the pelvis.
T2b: The cancer has spread to pelvic tissues besides the uterus and fallopian tubes but it is not 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 can not 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 of incomplete information.
Tis: Cancer cells are only in the inner lining of the fallopian tube. They have not 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 is not 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 is not 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 whether or not the cancer has spread to regional (nearby) lymph nodes.
Nx: No description of lymph node involvement is possible because of incomplete information.
N0: No lymph node involvement.
N1: Cancer cells are found in the lymph nodes close to tumor.
M categories
M categories indicate whether or not the cancer has spread to distant organs, such as the liver, lungs, or non-regional lymph nodes.
Mx: No description of distant spread is possible because of incomplete information.
M0: No distant spread.
M1: Cancer has spread to the inside of the liver, to the lungs, or other organs.
Grade categories
(The higher the grade, the more likely it is that the cancer will spread.)
Grade 1: Well differentiated -- looks similar to normal ovarian tissue.
Grade 2: Not as well differentiated -- looks less like ovarian tissue.
Grade 3: Poorly differentiated – does not look like ovarian tissue.
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. 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).
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 within both ovaries without any tumor 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 involved other organs (such as the uterus, fallopian tubes, bladder, the sigmoid colon, or the rectum) within the pelvis.
Stage IIA (T2a, N0, M0): The cancer has spread to or has actually 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 laboratory examination of the washings from the abdomen found evidence of cancer cells.
Stage III
The cancer involves 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 can see cancer involving the ovary or ovaries, but no cancer is grossly visible (can be seen without using a microscope) 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 present 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 of 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).
Survival by stage
The numbers below are based on patients diagnosed from 1988 to 2001. These numbers come from the National Cancer Institute, SEER Data Base.
Invasive epithelial ovarian cancer
Stage
Relative 5-Year Survival Rate
I
89%
IA
94%
IB
91%
IC
80%
II
66%
IIA
76%
IIB
67%
IIC
57%
III
34%
IIIA
45%
IIIB
39%
IIIC
35%
IV
18%
Ovarian tumors of low malignant potential
Stage
Relative 5-yr Survival Rate
I
99%
II
98%
III
96%
IV
77%
Germ cell tumors of the ovary
Stage
Relative 5-yr Survival Rate
I
98%
II*
80%
III
84%
IV
55%
*stage II cancer survival not based on many cases - may not be reliable
Fallopian tube carcinoma
Stage
Relative 5-yr Survival Rate
I
93%
II*
74%
III
66%
IV
40%
The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Five-year rates are used to produce a standard way of discussing prognosis. Of course, many people live much longer than 5 years. Five-year relative survival rates take into account that people will die of other causes and compare the observed survival with that expected for people without ovarian cancer. This is a better way to describe the deaths from ovarian cancer.
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