Ovarian cancer: What you need to know about stages, grades, types and survival rates
Ovarian cancer is a type of cancer that starts in the ovaries, a part of the female reproductive system. It’s also possible for this type of cancer to begin at the far end of the fallopian tube.
Ovarian cancer is classified by stage, grade and type. Ovarian cancer screening tests are used to help determine the classification of the tumor.
What is ovarian cancer staging and why is it used?
Ovarian cancer staging systems are used to determine the extent or progression of a patient’s cancer. Staging systems help describe the growth and spread of the cancer cells in the body.
The four stages of ovarian cancer are used by healthcare professional to:
- Describe how severe the ovarian cancer is
- Provide a prognosis or survival rate
- Determine the appropriate course of treatment
Staging systems are used during the diagnosis process. They may also be used following a diagnosis if the ovarian cancer has recurred following treatment, or to see how successful a particular treatment has been.
How is the stage of ovarian cancer determined?
A number of different types of tests are used to screen for ovarian cancer and they provide information that can help determine the stage the ovarian cancer has reached.
There are two staging systems that are used for ovarian cancer, which are essentially the same:
- The American Joint Committee on Cancer (AJCC) staging system
- The International Federation of Gynecology and Obstetrics (FIGO) staging system.
Both the AJCC and FIGO staging systems use three factors - T, N and M - to determine the stage of ovarian cancer
- T category measures the size or extent of the tumor. It looks at whether the cancer has spread outside of the ovary or fallopian tube and whether it has reached nearby organs like the bladder or uterus.
- N category measures whether the cancer has spread to nearby lymph nodes, including lymph nodes in the pelvis and the para-aortic lymph nodes, which sit around the aorta (the main artery that runs from the heart to the abdomen and pelvis).
- M category measures whether the cancer has metastasized or spread to the bones, liver or other distant organs. It also looks for signs of malignant pleural effusion, which is when fluid and cancer cells build up between the lungs and the chest wall.
Once the results of the T, N and M categories are known, stage grouping occurs. Stage grouping is a process used to determine the overall stage of the cancer.
In addition to staging ovarian cancer, these systems are also used to stage fallopian tube cancer and primary peritoneal cancer. These cancers are much rarer than ovarian cancer, but there are similarities between them and they are managed in the same way.
There are four main stages of ovarian cancer.
What are the four stages of ovarian cancer?
The four stages of ovarian cancer range from stage 1 (I) to stage 4 (IV). Stages are further split by letters. The higher the stage number, the more advanced the cancer is.
The stages outlined below are the ‘pathologic or surgical’ stages, which are determined in a lab using a tumor sample obtained during surgery. If surgery hasn’t been possible then the ‘clinical’ stage of the cancer may be determined based on the findings of the screening tests that have been completed.
Stage 1
Stage 1 ovarian cancer is when the cancer and is in one or both ovaries or fallopian tubes only. It is an early stage of ovarian cancer.
Stage |
Sub-stage |
Stage description |
TNM staging |
| IA |
The cancer is only in one ovary or fallopian tube and is confined to the inside of that ovary or tube. Cancer cells are not found in the fluid (ascites) or washings from the abdomen and pelvis. The cancer has not spread to nearby lymph nodes or distant sites. |
T1a-N0-M0 | |
| IB |
The cancer is in both ovaries or fallopian tubes, but is confined to the inside and is not on the outer surface of the ovaries or tubes. Cancer cells are not found in the fluid (ascites) or washings from the abdomen and pelvis. The cancer has not spread to nearby lymph nodes or distant sites. |
T1b-N0-M0 | |
| IC | IC1 |
The cancer is in one or both ovaries or fallopian tubes. During surgery the tissue (capsule) around the tumor broke and cancer cells leaked into the abdomen and pelvis - surgical spill. |
T1c1-N0-M0 |
| IC | IC2 |
The cancer is in one or both ovaries or fallopian tubes. Cancer cells are on the outer surface of at least one ovary or fallopian tube. |
T1c2-N0-M0 |
| IC | IC3 |
The cancer is in one or both ovaries or fallopian tubes. Cancer cells are found in the fluid (ascites) or washings from the abdomen and pelvis. |
T1c3-N0-M0 |
Stage 2
Stage 2 ovarian cancer is when the cancer is in one or both ovaries or fallopian tubes and has spread to other organs (such as the uterus, bladder, the sigmoid colon, or the rectum) within the pelvis (below the pelvic brim) or there is primary peritoneal cancer. This is an early-stage of ovarian cancer.
Stage |
Stage description |
TNM staging |
| IIA |
The cancer has spread to or grown into the uterus, and/or the fallopian tubes and/or the ovaries. The cancer has not spread to the nearby lymph nodes or to distant sites. |
T2a-N0-M0 |
| IIB |
The cancer is on the outer surface of or has grown into other nearby pelvic organs such as the bladder, the sigmoid colon, or the rectum. The cancer has not spread to nearby lymph nodes or to distant sites. |
T2b-N0-M0 |
Stage 3
This stage of ovarian cancer is at an advanced stage and is one or both ovaries or fallopian tubes and has spread beyond the pelvis to the lining of the abdomen (peritoneum) or to nearby lymph nodes.
Stage |
Sub-stage |
Stage description |
TNM staging |
| IIIA | IIIA1 |
The cancer is in one or both ovaries or fallopian tubes, or there’s a primary peritoneal cancer and it may have spread or grown into nearby organs in the pelvis. The cancer has spread to the retroperitoneal (pelvic and/or para-aortic) lymph nodes only, but not to distant sites. |
T1/T2-N1-M0 |
| IIIA | IIIA2 |
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 in the abdomen (outside of the pelvis) to the naked eye, but tiny deposits of cancer are found in the lining of the abdomen when it is examined in the lab. The cancer may or may not have spread to retroperitoneal lymph nodes. It has not spread to distant sites. |
T3a2-N0/N1-M0 |
| IIIB |
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 the surgeon can see the cancer, but it is no bigger than ¾ inch (2 cm) across. The cancer may or may not have spread to retroperitoneal lymph nodes, but has not spread to distant sites. |
T3b-N0/N1-M0 | |
| IIIC |
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 the surgeon can see the cancer and it is bigger than ¾ inch (2 cm) across and may be on the outside (the capsule) of the liver or spleen. The cancer may or may not have spread to retroperitoneal lymph nodes, but has not spread to distant sites. |
T3c-N0/N1-M0 |
Stage 4
Stage 4 ovarian cancer is at an advanced stage and the cancer has spread to distant sites in the body.
Stage |
Stage description |
TNM staging |
| IVA | Cancer cells are found in the fluid around the lungs (malignant pleural effusion) with no other areas of cancer spread such as the liver, spleen, intestine or lymph nodes outside the abdomen. | Any T and N, M1a |
| IVB | The cancer has spread to the inside of the spleen or liver, to lymph nodes other than the retroperitoneal lymph nodes, and/or to other organs or tissues outside the peritoneal cavity such as the lungs and bones. | Any T and N, M1b |
In addition to the TNM coding mentioned above, these are other codes that may be used:
- Tumor T
- TX - tumor cannot be assess due to lack of information
- T0 - no evidence of a primary tumor
- Regional lymph nodes N
- NX - regional lymph nodes cannot be assessed
- N0 - no regional lymph node metastasis
- N1 - regional lymph nodes metastasis
- Distant metastasis M
- MX - distant metastasis cannot be assessed
- M0 - no distant metastasis
- M1 - distant metastasis excluding peritoneal metastasis
Grading of ovarian cancer
Ovarian cancer is also assigned a ‘grade’. The grade indicates how quickly the cancer may spread and grow - how aggressive it is - and is based on how the cells look under a microscope.
Lower grade cancer cells look similar to normal cells, while higher grade cancers that are likely to grow and spread more quickly look different.
Ovarian cancer is graded in the following way:
- Grade 1 - low grade - expected to grow slowly
- Grade 2 - moderate grade - expected to grow more quickly than grade 1
- Grade 3 - high grade - expected to grow quickly
Types of ovarian cancer
There are three main types of cells that make up the ovaries including epithelial, germ and stromal cells. Each cell type can develop into a different ovarian tumor type.
Types |
Location of cells |
Sub-types |
Common or rare |
Age at diagnosis |
| Epithelial ovarian cancer | Epithelial cells are located on the outside of the ovary in a layer of cells called the epithelium. | Subtypes include serous, mucinous, endometrioid and clear cell cancers. | Common - 90% of cases | Mostly greater than 60 years of age |
| Germ cell ovarian cancer | Germ cells are located on the inside of the ovaries. Germ cells mature into ova or eggs. | Rare - 4% of cases | Mostly less than 40 years of age | |
| Stromal cell ovarian cancer | Stromal cells make up the connective tissue inside the ovaries. Stromal cells also make the hormones estrogen and progesterone. | Rare | Mostly between 40-60 years of age |
Ovarian cancer survival rates
Survival rates vary depending on the stage, grade and type of ovarian cancer you have. Age, general health and response to treatment are other factors that may also have an impact upon the outcome.
Cancer survival rates are typically reported as the percentage of patients still alive after five years. These figures are estimates only - they don’t take into account how a patient responds to treatment or how the cancer spreads, for example. They are also based on data from women who were diagnosed and treated some time ago.
5-year relative survival rate by stage
The survival of ovarian cancer patients who all have the same stage and type of ovarian cancer at diagnosis is compared with that of people in the general population to determine the 5-year survival rates.
The SEER (Surveillance, Epidemiology, and End Results) database is used to track the 5-year survival rates for ovarian cancer in the US.
Stage |
Percentage of cases by stage |
Overall 5-year relative survival rate* |
5-Year relative survival rate -
|
5-Year relative survival rate -Ovarian stromal tumors |
5-Year relative survival rate -Germ cell ovarian tumors |
5-Year relative survival rate -Fallopian tube cancer |
|
Localized - confined to the primary site (Stage 1 and 2) |
16% | 93% | 93% | 98% | 98% | 95% |
|
Regional - spread to regional lymph nodes (Stage 3) |
21% | 75% | 75% | 89% | 94% | 53% |
| Distant - cancer has metastasized and spread to distant sites (Stage 4) |
57% | 30% | 31% | 60% | 73% | 45% |
| Unknown | 5% | 27% |
*SEER 18 2011–2017- all races - females by SEER summary stage 2000
Bottom line
Knowing the stage, grade and type of ovarian cancer you have helps your healthcare provider to decide on the best course of treatment for you and enables them to provide you with more information about what the likely outcome of your treatment will be.
Early-stage, low-grade ovarian cancers are associated with more favorable prognosis or outcome if treated. The more advanced the stage of ovarian cancer at diagnosis, the more likely it is to result in a diagnosis of terminal or end-stage cancer.
Article references
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- American Cancer Society (ACS). Cancer Staging. June 18, 2020. Available at: https://www.cancer.org/treatment/understanding-your-diagnosis/staging.html. [Accessed June 25, 2021].
- Berek JS, Kehoe ST, Kumar L, Friedlander M. Cancer of the ovary, fallopian tube, and peritoneum. Int J Gynaecol Obstet. 2018;143 Suppl 2:59-78. doi:10.1002/ijgo.12614. https://obgyn.onlinelibrary.wiley.com/doi/10.1002/ijgo.12614
- Cancer Council NSW. Staging and prognosis for ovarian cancer. May 2020. Available at: https://www.cancercouncil.com.au/ovarian-cancer/diagnosis/staging-prognosis/. [Accessed 25 June, 2021].
- Cancer Council NSW. Understanding Ovarian Cancer. A guide for people with cancer, their families and friends. April 2020, Available at: https://www.cancercouncil.com.au/wp-content/uploads/2016/07/Understanding-Ovarian-Cancer-2020-1.pdf. [Accessed 25 June, 2021].
- Ovarian Cancer Research Alliance (OCRA). Stages of Ovarian Cancer. Available at: https://ocrahope.org/patients/about-ovarian-cancer/staging/. [Accessed June 25, 2021].
- American Cancer Society (ACS). Survival Rates for Ovarian Cancer. January 25, 2021. Available at: https://www.cancer.org/cancer/ovarian-cancer/detection-diagnosis-staging/survival-rates.html. [Accessed June 25, 2021].
- NIH, National Cancer Institute - Surveillance, Epidemiology, and End Results (SEER) Programme. Cancer Stat Facts: Ovarian Cancer. Available at: https://seer.cancer.gov/statfacts/html/ovary.html. [Accessed June 25, 2021].
- Cancer Treatment Centers of America. Ovarian cancer stages. May 24, 2021. Available at: https://www.cancercenter.com/cancer-types/ovarian-cancer/stages. [Accessed June 25, 2021].
