Staging and grades
Cases of ovarian cancer are categorised by stage, which describes how far the cancer has spread, and by grade which indicates how active the cancer is. A new system of grading ovarian cancer has been used since January 2014 which includes more detailed classifying than the former system which dated from 1988. The new system also applies to fallopian tube and primary peritoneal cancers.
This is the earliest stage and indicates that the cancer affects only one or both ovaries or fallopian tubes. At this stage the cancer may cause few symptoms and most women are not aware that anything is wrong. Sometimes stage 1 cancers do cause symptoms such as discomfort, passing urine more frequently or constipation. This may be due to the tumour pressing on the bladder or bowel.
Only a small number of women have their cancer diagnosed at this early stage. If the cancer is confirmed as stage 1 then the outlook is good, particularly if the cancer is contained within one ovary (stage 1a) or both ovaries (stage 1b) when surgery alone may be enough to treat it.
Stage 1c is when the cancer is limited to one or both ovaries or fallopian tubes, but cells may have leaked into the abdomen during initial investigative surgery (stage 1c1); the ovary may have ruptured before surgery or there may be a tumour on the surface of the ovary or fallopian tube (stage 1c2): or there may be cancer cells present in abdominal fluids (stage 1c3). Stage1c ovarian cancer usually requires chemotherapy as well as surgery.
At this stage the cancer has spread outside the ovary into the pelvis or has gone into the uterus (womb). Stage 2 ovarian cancer is found in very few women because the lining of the pelvis and abdomen are not separated, so the cancer usually spreads to the abdomen at the same time as it spreads to the pelvis.
Ovarian cancer is classified as stage 2a when it has spread to the uterus or fallopian tubes. Stage 2b is when it has spread to other pelvic tissues. Women with stage 2 ovarian cancer are likely to be advised to have chemotherapy as well as surgery.
This is the most common stage at which ovarian cancer is diagnosed. At this stage the cancer may have spread beyond the pelvis to the lymph glands in the peritoneum (the lining of the abdominal cavity).
Stage 3a1 is when the cancer has spread only to the peritoneal (abdominal) lymph glands. Stage 3a1(i) means the disease in the lymph measures up to 10 mm in diameter and stage 3a1(ii) means that the lymph gland metastases (cancer that has spread) measures more than 10mm. Stage 3a2 is when microscopic disease has spread beyond the pelvis with or without affecting the peritoneal (abdominal) nodes.
At stage 3b visible disease has spread beyond the pelvis and measures less than two centimetres, with or without affecting the peritoneal nodes; stage 3c is visible disease beyond the pelvis measuring more than two centimetres, with or without including the peritoneal nodes including the surface of the liver and spleen but not within those organs.
The symptoms at this stage are indigestion, constipation, poor appetite, abdominal bloating and discomfort. These are usually due to pressure on the bowel caused by fluid and the tumour. Cancer in the lining of the abdomen (peritoneum) may release fluid which collects inside, called ascites.
When stage 3 ovarian cancer is discovered, the aim of initial surgery is to remove as much of the disease as possible. Further treatment usually involves chemotherapy and a second operation during the chemotherapy may be suggested.
A small number of women with ovarian cancer are found to have stage 4 disease. This is when the cancer has spread beyond the abdomen to more distant organs.
Stage 4a is when the cancer causes a build-up of fluid between the lining of the lungs and the chest wall, called a pleural effusion. This can cause breathlessness which may be the first symptom of the cancer. Stage 4b is when the cancer has spread within other more distant organs including lymph nodes outside the abdominal cavity.
Women with stage 4 ovarian cancer may be treated by surgery followed by chemotherapy, or by chemotherapy alone.
Grading is to indicate a factor in the cancer’s prognosis. It describes how active or aggressive the cancer is. There are three grades; grade I is low, grade II is intermediate and grade III is high.. However, this is only one of a number of prognostic factors and cannot be taken in isolation. For example, a grade III stage Ia cancer will usually have a better outlook than one at stage IIIc grade I.
Last review April 2018
Date of next review April 2020