The short answer
About 85 to 90 percent of ovarian cancers are epithelial tumors. Germ cell tumors and sex cord-stromal tumors are much less common but often have a better outlook, especially in younger patients.
Epithelial tumors make up about 85 to 90 percent of ovarian cancers.
Germ cell tumors make up less than 2 percent of ovarian cancers and often occur in younger people.
Sex cord-stromal tumors are also uncommon and start in the cells that support the ovary.
Germ cell and stromal tumors often have a better outlook than epithelial ovarian cancer.
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The full explanation.
The simple version
Ovarian tumors are grouped by the type of cell they start in. There are three main groups. They behave quite differently from one another.
The three main types
- Epithelial tumors make up about 85 to 90 percent of ovarian cancers. They start in the cells covering the surface of the ovary, or lining the fallopian tube. This is the type most people mean when they say "ovarian cancer."
- Germ cell tumors make up less than 2 percent of ovarian cancers. They start in the egg-producing cells. They are more common in children, teens, and younger adults. The outlook is usually good. More than 9 in 10 people live at least five years.
- Sex cord-stromal tumors are less common than epithelial tumors. They start in the cells that support the ovary, and they sometimes make hormones. When these tumors are cancer, the long-term outlook is often good. More than 75 percent of people live long term.
In short: epithelial tumors are the most common. Germ cell and stromal tumors are rarer, and often more treatable.
Why type matters for treatment
These three tumor types come from different cells. So they grow and respond to treatment in different ways. Epithelial ovarian cancer is usually treated with surgery and platinum-based chemotherapy. Germ cell tumors often respond very well to a different mix of chemotherapy drugs. Surgery can sometimes spare the healthy ovary and the uterus. That matters most to younger patients who hope to have children later. Stromal tumors have their own approach, which sometimes includes hormone-related therapies.
Why this matters for you
The exact type is one of the most important facts in an ovarian cancer diagnosis. It shapes the treatment path. It also shapes what outlook is realistic.
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Words to know
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Common questions
What is the most common type of ovarian cancer?
Epithelial ovarian cancer is by far the most common type, making up about 85 to 90 percent of cases. It starts in the cells covering the surface of the ovary or lining the fallopian tube.
What are germ cell tumors?
These start in the egg-producing cells of the ovary. They make up less than 2 percent of ovarian cancers and tend to occur more often in children, teens, and younger adults. They generally have a favorable outlook, with more than 90 percent of patients surviving at least five years.
What are stromal tumors?
Sex cord-stromal tumors start in the connective tissue cells that support the ovary and sometimes produce hormones. They are less common than epithelial or germ cell tumors and often have a good long-term outlook.
Does the type affect which treatment I get?
Yes. Epithelial ovarian cancer is generally treated with surgery and chemotherapy drugs different from those used for germ cell or stromal tumors, which often respond to different chemotherapy regimens and may have a better prognosis at a given stage.
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Last updated: 2026-08-11Next planned review: 2027-08-03
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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