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Beginner 4 min readSource checked

What Is Ovarian Cancer? Where It Starts

Just been diagnosed with Ovarian Cancer? Start here instead

A plain-language overview of ovarian, fallopian tube, and primary peritoneal cancer, where it starts, and how it is found

NCI source

National Cancer Institute

A female doctor talks with a teenage girl and woman in a clinic room
A female doctor talks with a teenage girl and woman in a clinic room

Key fact

Ovarian epithelial cancer, fallopian tube cancer, and primary peritoneal cancer form in the same kind of tissue and are treated the same way.

The short answer

Ovarian epithelial cancer, fallopian tube cancer, and primary peritoneal cancer form in the same kind of tissue and are treated the same way. The ovaries are a pair of organs in the female reproductive system that make eggs and hormones. These cancers often cause no early symptoms and are frequently advanced when found.

  • Ovarian epithelial cancer, fallopian tube cancer, and primary peritoneal cancer form in the same kind of tissue and are treated the same way.

  • The ovaries are a pair of almond-sized organs in the pelvis, one on each side of the uterus, that make eggs and female hormones.

  • These cancers may cause no early signs, so they are often advanced when found.

  • A family history of ovarian cancer raises the risk, and about 20% of ovarian cancers are hereditary.

Subjective: What you might experience

This section describes the symptoms and history a patient might report to their doctor.

Bloating or abdominal swelling that persists.

Feeling full quickly or trouble eating.

Pelvic or abdominal pain or pressure.

Urinary urgency or needing to urinate often.

Symptoms are often vague and easy to overlook, which contributes to later diagnosis.

Risk history

age, family history, BRCA1/BRCA2 mutations, and other inherited syndromes.

Objective: Tests and findings

Pelvic exam and transvaginal ultrasound to evaluate the ovaries.

CA-125 blood test (a tumor marker that may be elevated).

CT or MRI of the abdomen and pelvis to assess extent of disease.

Tissue diagnosis usually obtained at surgery; biopsy in some cases.

Genetic testing (BRCA and others), which also guides therapy.

Interactive anatomy guide

Explore where cancers start and how they are found, on an interactive body map.

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Assessment: Staging and prognosis

Most are epithelial ovarian cancers; diagnosis confirmed by pathology.

Staged surgically with the FIGO/TNM systems, often diagnosed at a more advanced stage.

BRCA and homologous-recombination status guide targeted treatment.

Extent of spread within the abdomen assessed for surgical planning.

Plan: The treatment approach

Surgery to remove as much tumor as possible (debulking) and to stage the disease.

Chemotherapy (usually platinum-based) before and/or after surgery.

Maintenance targeted therapy (e.g., PARP inhibitors) for eligible patients.

Clinical trials for advanced or recurrent disease.

CA-125 and imaging surveillance after treatment.

These are simplified, educational SOAP-style summaries showing the kinds of findings clinicians document when evaluating each cancer, based on National Cancer Institute resources. They describe typical diagnostic criteria and workups — not a real patient, and not medical advice. Real clinical notes are individualized. Always rely on your own care team. Based on National Cancer Institute educational content. Educational only — not medical advice.

Words to know

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Common questions

Where does ovarian cancer start?

The ovaries are a pair of organs in the female reproductive system, in the pelvis, one on each side of the uterus. Ovarian epithelial cancer forms in the tissue covering the ovary. Closely related cancers form in the lining of the fallopian tube or the peritoneum, the tissue that lines the abdomen. These cancers form in the same kind of tissue and are treated the same way.

What do the ovaries do?

Each ovary is about the size and shape of an almond. The ovaries make eggs and female hormones. Eggs pass from the ovaries, through the fallopian tubes, to the uterus.

Why is ovarian cancer often found late?

Ovarian epithelial, fallopian tube, or peritoneal cancer may not cause early signs or symptoms. When signs or symptoms do appear, the cancer is often advanced. These signs may include pain, swelling, or pressure in the abdomen or pelvis, feeling full quickly, and needing to urinate often.

Does family history affect ovarian cancer risk?

Yes. Women who have a family history of ovarian cancer in a first-degree relative (mother, daughter, or sister) are at increased risk. Hereditary ovarian cancer makes up about 20% of all cases. Some cases are linked to inherited changes in the BRCA1 or BRCA2 genes.

Are ovarian, fallopian tube, and peritoneal cancers the same?

Ovarian epithelial cancer, fallopian tube cancer, and primary peritoneal cancer form in the same type of tissue and are treated the same way. Cancer sometimes begins near the end of a fallopian tube and spreads to the ovary, or begins in the peritoneum and spreads to the ovary.

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Knowledge Check

0 of 4 answered

  1. Q1.According to this article, what do the ovaries do?
  2. Q2.According to this article, how are ovarian, fallopian tube, and primary peritoneal cancers related?
  3. Q3.According to this article, why is ovarian cancer often found late?
  4. Q4.According to this article, what can raise the risk of ovarian cancer?

This self-assessment checks understanding of educational content only. It is not medical advice.

Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.

Sources last checked: 2026-07-21 what this meansLast updated: 2026-08-10Next planned review: 2027-07-21

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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.

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General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team 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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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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