Ovarian Cancer: Stages and Subtypes
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Sign Up for FORCE NewslettersOvarian, , and Primary Peritoneal Cancer Stages and Subtypes
Ovarian, , and primary peritoneal cancer are very closely related. Although they each begin in different parts of the reproductive tract, the cells look and behave the same and similar treatments are used for each. Primary peritoneal cancer arises from the lining of the abdomen, also known as the peritoneum.
Subtypes and grades
After surgery confirms cancer, the pathologist looks closely at the type of cells found in the tumor for additional clues on how to best treat it. The subtypes can also be classified as high-grade or low-grade depending on how quickly the cancer cells are growing and dividing and the presence of certain genetic mutations within the tumor. The subtype and grade affect treatment options and prognosis. The most common subtypes of ovarian cancer belong to a group called epithelial cancers, that arise from the outer lining of the ovaries and tubes. Less commonly, ovarian cancers may arise from other tissue in the ovaries.
Subtype |
Description |
high grade serous |
This is the most common subtype of ovarian cancer. This subtype is often seen in women with BRCA1 or BRCA2 mutations, although other mutations, including PALB2, MLH1, MSH2 and MSH6 have been found as well. |
endometrioid |
This is the second most common subtype of ovarian cancer. This is the subtype most often seen in women with Lynch syndrome who are diagnosed with ovarian cancer. Endometriosis may slightly increase the risk for developing endometrioid ovarian cancer. |
clear cell |
This is a rare subtype. It may be seen in women with Lynch syndrome who are diagnosed with ovarian cancer. Endometriosis may slightly increase the risk for developing clear cell ovarian cancer. |
mucinous |
This is a rare subtype. It may be seen in women with Lynch syndrome who are diagnosed with ovarian cancer. |
low grade serous |
This is a rare subtype of ovarian cancer that tends to occur in younger women. This subtype is not typically found in people with inherited mutations. |
stromal cell |
This rare subtype develops in the cells that produce the hormones estrogen and progesterone. Many stromal tumors are benign. People with STK11 mutations have an increased risk for developing ovarian stromal tumors. |
germ cell |
This is a rare subtype that forms in the cells that mature into eggs. Germ cell tumors tend to occur in younger women. Many germ cell cancers are benign, but some can be cancerous. |
carcinosarcoma |
In the past, this subtype was called malignant mixed Mullerian tumors (MMMT). These are very aggressive cancers. Although very rare, there have been cases of carcinosarcomas reported in people with BRCA1 and BRCA2 mutations. |
Subtypes of ovarian cancer |
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Stages of ovarian cancer
The of a cancer refers to whether it has spread beyond the ovaries and tubes, and if it has, the location in the body where it has spread. Measuring the of ovarian cancer helps doctors decide how to treat it. Doctors may order additional tests such as chest XRAYS, chest, pelvic and abdominal CT, or PET scans to learn if the cancer has spread beyond the ovaries and tubes.
Stage |
Description |
Stage 1 |
The cancer is confined to the ovary or fallopian tube. |
Stage 2 |
The cancer is confined to the pelvis. |
Stage 3 |
The cancer is confined to the upper abdomen. |
Stage 4 (metastatic) |
The cancer has spread beyond the abdomen. |
Stages of ovarian cancer |
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Stages 3 and 4 are considered advanced ovarian cancer.
STIC lesions
Many women at high risk for ovarian cancer remove their ovaries and to lower their risk for cancer. In some cases, doctors may find a pre-cancerous change in the , known as serous tubal intraepithelial carcinoma (STIC) lesions. People with STIC lesions may have an increased risk for developing primary peritoneal cancer after surgery. Researchers are studying whether additional treatment for people with STIC lesions improves their outcomes.
Doctors may order additional tumor tests to help guide treatment. For some people with advanced cancers, tumor testing can look for further clues to help guide the choice of targeted therapies.