Doctors stage ovarian cancer from 1 to 4; stage 1 ovarian cancer is the least advanced and stage 4 ovarian cancer the most. Generally, patients at the same stage get similar treatment, although other factors (such as a patient’s overall health) influence a doctor’s decision-making. Physicians perform a series of diagnostic tests to stage ovarian cancer. These tests can involve surgery to get tissue samples from throughout the pelvis and abdomen and possibly elsewhere in the body. Pathologists examine these samples under a microscope, searching for cancer cells. For ovarian cancer, physicians use two systems that are virtually identical: the FIGO (International Federation of Gynecology and Obstetrics) system and the AJCC (American Joint Committee on Cancer) TNM staging system. These evaluate the extent of a patient’s cancer using three key factors:
T (Tumor) This indicates the extent of the tumor. Is it confined to the ovaries or fallopian tube or has it reached the uterus, bladder, or other nearby pelvic organs?N (Node) Has the cancer spread to nearby lymph nodes in the pelvis or the para-aortic lymph nodes around the aorta (the body’s main artery that runs from the heart down behind the abdomen and pelvis)?M (Metastasis) Has the cancer spread to the fluid around the lungs or to distant organs or tissues, like the liver?
Doctors also add a number or letter to each T, N, or M assessment to provide additional detail. Typically, the higher the number, the more advanced the cancer. A calculation that combines the T, N, and M ratings ultimately leads to an overall stage. Fallopian tube cancer and primary peritoneal cancer (cancer in the thin layer of tissue that lines the abdomen) are closely related to ovarian cancer, and are included in the stages below.
Ovarian Cancer Stage 1
The cancer is contained within the ovary (or ovaries) or fallopian tube(s). Stage 1A The cancer is in one ovary, confined to the inside; or the cancer is in one fallopian tube, confined to the inside. Stage 1B The cancer is in both ovaries or fallopian tubes but not on their outer surfaces. Stage 1C The cancer is in one or both ovaries or fallopian tubes and any of the following conditions are present:
The tissue (capsule) surrounding the tumor broke during surgery — a condition known as surgical spill — which could allow cancer cells to leak into the abdomen and pelvis (stage 1C1).Cancer is on the outer surface of at least one of the ovaries or fallopian tubes, or the capsule burst before surgery (stage 1C2).Cancer cells are found in the fluid (ascites) or washings from the abdomen and pelvis (stage 1C3).
Ovarian Cancer Stage 2
The cancer is in one or both ovaries or fallopian tubes and has spread to nearby pelvic organs (such as the uterus, bladder, the sigmoid colon, or the rectum), or there is primary peritoneal cancer. Stage 2A The cancer has spread to or grown into the uterus or fallopian tubes, or the ovaries. Stage 2B The cancer is on the outer surface of or has grown into nearby pelvic organs.
Ovarian Cancer Stage 3
Stage 3A1 The cancer is in one or both ovaries or fallopian tubes, or there is primary peritoneal cancer and it may have spread or grown into nearby pelvic organs. It has spread to the pelvic or para-aortic (retroperitoneal) lymph nodes only. Stage 3A2 The cancer is in one or both ovaries or fallopian tubes, or there is primary peritoneal cancer and it has spread or grown into organs outside the pelvis. During surgery, no cancer is visible to the naked eye in the abdomen (outside the pelvis), but tiny deposits of cancer are found in the lining of the abdomen when it is examined in the lab. The cancer might or might not have spread to the pelvic or para-aortic lymph nodes. Stage 3B The cancer is in one or both ovaries or fallopian tubes, or there is primary peritoneal cancer and it has spread or grown into organs outside the pelvis. The deposits of cancer are large enough for the surgeon to see, but are no bigger than 2 centimeters (about ¾ inch) across. The cancer may or may not have spread to the retroperitoneal lymph nodes. Stage 3C This is similar to stage 3B except that the deposits of cancer are larger than 2 centimeters across and may be on the outside (the capsule) of the liver or spleen.
Ovarian Cancer Stage 4
Stage 4A Cancer cells are present in the fluid around the lungs (called a malignant pleural effusion) with no other areas of cancer spread. Stage 4B The cancer has spread to the inside of the spleen or liver, to lymph nodes other than the retroperitoneal ones, or to other organs or tissues outside the peritoneal cavity, such as the lungs and bones. If the cancer cells look like healthy tissue with different cell groupings, it’s called “low-grade.” If they look very different and are poorly differentiated, doctors will label it “high-grade.” The description of tumor grades are:
GX This describes a grade that can’t be evaluated.GB The tissue that’s examined is considered borderline cancerous.G1 The tissue contains lots of healthy-looking cells and is considered well-differentiated.G2 The tissue contains more cells that appear abnormal than healthy. It’s considered moderately differentiated.G3 to G4 The tissue contains more cells that appear abnormal and lacks normal tissue structures. It’s considered poorly differentiated.
The Relationship Between Cancer Stage and Survival Rates
With ovarian cancer, as with other cancers, early-stage disease is easiest to treat, with the best prognosis. The problem with ovarian cancer is that it can be asymptomatic in its earliest stages; if it does cause symptoms, such as bloating or abdominal pain, they can be vague and easy to blame on more common and less life-threatening health conditions. Roughly 8 in 10 women are diagnosed after their cancer has spread beyond the ovaries. (3) Women treated for early-stage ovarian cancer (stages 1A and 1B) have a five-year survival rate of 93.1 percent, according to the National Cancer Institute. (4) But the five-year relative survival rate for all ovarian cancer stages is 49.7 percent. Still, staging can’t predict life expectancy for every patient. Other factors come into play, such as your overall health, your age, and how well your cancer responds to treatment. (5) Additional reporting by Julie Marks and Leona Vaughn.
