Ovarian Cancer

Overview and Staging

Ovarian cancer forms in the ovaries, which produce eggs and are the main source of the female hormones estrogen and progesterone. The eggs travel from the ovaries through the fallopian tubes into the uterus. Women have two ovaries, one on each side of the uterus.

There are three types of ovarian cancer. Each is named for the type of cell where it began:

  • Epithelial carcinomas begin in the cells that line the outer surface of the ovaries. It is the most common type of ovarian cancer.
  • Germ cell tumors originate in the egg-producing cells of the ovaries.
  • Stromal cell tumors start in the connective tissue cells that hold the ovaries together and produce hormones.

Fallopian tube cancer, the rarest gynecologic cancer, is related to ovarian cancer. Some researchers think that ovarian cancer actually starts in the fallopian tubes. Treatment for fallopian tube cancer is often the same as that for ovarian cancer.

Diagnosing and staging

To diagnose ovarian cancer, your doctor will perform a physical exam and may order imaging tests. A biopsy is the only way to definitively diagnose ovarian cancer. Some of the tests done to diagnose your cancer will also help your doctor stage it. Staging cancer refers to determining the extent of cancer based on the size of the tumor and whether it has spread (and, if so, how far).

The staging process for ovarian cancer depends on several factors. It is based on results of physical examinations, imaging tests and the evaluation of surgically removed tissue samples. Knowing your stage helps you and your health care team choose the best treatment option for you.

To determine how far the cancer cells have spread, your surgeon might remove nearby lymph nodes, tissue and fluid within the pelvic and/or abdominal cavity for microscopic observation. The pathologist’s review of these samples will help determine an accurate stage, which is essential in establishing the most effective treatment plan for your specific type and stage of ovarian cancer.

Ovarian cancer is classified according to the tumor, node, metastasis (TNM) system developed by the American Joint Committee on Cancer. The tumor (T) is categorized according to its size and location, whether cancer cells are found in nearby lymph nodes (N), and whether cancer has metastasized (M) or spread to other parts of the body. Once an ovarian cancer has been classified with this system, an overall stage is assigned (see Staging Illustrations).

Table 1. TNM Ovarian Cancer Classifications

Classification Definition
Tumor (T)
Tumor is limited to one or both ovaries.
Tumor is contained within one ovary. No part of the tumor has spread to the surface of the ovary, and no cancer cells are found in the abdominal fluid.
There are encapsulated (self-contained) tumors in both ovaries, but no tumor is touching an ovarian surface. No cancer cells are found in the abdominal fluid.
The tumor is in one or both ovaries, but the capsule has ruptured (burst), or the tumor has spread to the ovarian surface, or cancer cells are found in the abdominal fluid.
Tumor involves one or both ovaries and has spread into the pelvis.
Tumor has grown into the uterus and/or fallopian tubes, but no cancer cells are found in the abdominal fluid.
There is cancer in other pelvic tissue, but no cancer cells are found in the abdominal fluid.
Tumor has grown into the pelvic area, such as in T2a or T2b, but cancer cells also are detected in the abdominal fluid.

Tumor involves one or both ovaries and cancerous cells can be seen when tissue or fluid sample is viewed under a microscope into the abdominal area outside the pelvis or has spread to pelvic lymph nodes.
Microscopic metastasis is in the peritoneal area (the tissue that lines the abdominal wall and covers most of the organs in the abdomen) beyond the pelvis.
Metastasis measuring 2 cm (a little less than 1 inch) or smaller is discovered outside the pelvis.
Metastasis larger than 2 cm is in areas outside the pelvis and/or the cancer has spread to the pelvic lymph nodes.
Node (N)
Nx The regional lymph nodes cannot be evaluated.
N0 No cancer was found in the regional lymph nodes.
N1 The cancer has spread to the pelvic lymph nodes.
Metastasis (M)
M0 There is no cancer beyond the peritoneal area.
M1 The cancer has spread beyond the peritoneal area.

Table 2. Stages of Ovarian Cancer

Stage TNM Classification
T1, N0, M0
T1a, N0, M0
T1b, N0, M0
T1c, N0, M0
T2, N0, M0
T2a, N0, M0
T2b, N0, M0
T2c, N0, M0
T3, N0, M0
T3a, N0, M0
T3b, N0, M0
T3c, N0, M0
Any T, N1, M0
IV Any T, any N, M1




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