By classifying ovarian cancer according to type and stage – from the earliest to the most advanced – Memorial Sloan Kettering doctors can prepare a treatment plan that’s customized specifically to your needs and condition. When learning about ovarian cancer, you may often see fallopian tube cancer and primary peritoneal cancer mentioned as well. This is because these three cancers are all treated the same way.
Fallopian tubes provide the path for eggs to travel from the ovaries to the uterus. The peritoneal cavity is the part of the abdomen that holds most of the abdominal organs, such as the uterus, liver, and spleen. The peritoneum is the lining of this cavity.
There are several types of ovarian cancer, which begin from these cell types:
- Surface epithelium, which involves cells that cover the ovaries’ lining
- Germ cells, which involve cells that will form eggs
- Stromal cells, which involve cells that release hormones and connect the different structures of the ovaries
After ovarian cancer is diagnosed, your MSK specialist needs to know its stage to determine how far it may have spread. To do this, your surgeon will remove the tumor, as well as small samples of tissue from within the abdomen, including from the other ovary, fallopian tubes and peritoneum. (Your peritoneal cavity is where most of your abdominal organs are located.) These samples are sent to our laboratory for one of our expert pathologists to examine them for cancer cells with a microscope and with other tools.
Your MSK specialist will then receive the pathology report, which lists the type of cancer that was found, the size of the tumor, if the cancer was contained within the ovary or if it had spread, the diagnosis, and the stage.
What are the four stages of ovarian cancer?
There are four stages of cancer of the ovaries, fallopian tubes and peritoneum, ranging from early to advanced cancer.
Stage I ovarian cancer is considered an early cancer.
This stage is divided into three substages, A, B, and C:
Stage IA: cancer cells are present in one ovary or fallopian tube.
Stage IB: cancer cells are present in both ovaries, or in both fallopian tubes.
Stage IC: cancer cells are present in one or both ovaries or fallopian tubes, and one of the following:
- The outside of the ovaries or fallopian tubes has cancer cells;
- The covering of the ovary, called the capsule, has broken open; or
- Cancer cells are found in your peritoneal cavity, its tissue lining, or fluid from your abdomen.
Stage II cancer has begun to spread. This stage is divided into two substages, A and B:
Stage IIA: cancer has spread from the ovary or ovaries to the fallopian tubes and/or the uterus, or it has spread from the fallopian tubes to the ovaries and/or uterus.
Stage IIB: cancer has spread in the peritoneal cavity to your bladder, colon, or rectum.
Stage III cancer is more advanced. This stage is divided into three substages, A, B, and C:
Stage IIIA is defined in one of two ways:
- cancer cells have spread to the closest lymph nodes, called the retroperitoneal lymph nodes.
- The surgeon cannot see the cancer with the naked eye, but using a microscope to examine the samples, the pathologist can see that the cancerous cells have spread to the outside the pelvis to the peritoneum (lining). The cancer may also have spread to nearby lymph nodes.
Stage IIIB: cancer inside the peritoneum can be seen by the surgeon, but is still 2 centimeters or smaller. The cancer has also spread outside the pelvis. It may have spread to nearby lymph nodes.
Stage IIIC: the cancer has grown to 2 centimeters in diameter or larger, and has spread to the peritoneum outside the pelvis. It may also have spread the outside of the liver and/or the spleen, as well as nearby lymph nodes.
Stage IV cancer is the most advanced form of ovarian cancer.
There are two substages, A and B:
Stage IVA: cancer cells are found in extra fluid that has built up around the lungs.
Stage IVB: cancer has spread to organs and tissues outside the abdomen, including lymph nodes in the groin.
Whatever type or stage your condition may be, MSK doctors will find a way to build a treatment plan customized for you.
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