Ovarian cancer is a group of cancers that begin in or near the ovaries, the two small organs on either side of the uterus that produce eggs and hormones. It accounts for more deaths than any other cancer of the female reproductive system, in part because symptoms are vague and easily mistaken for digestive problems. When caught early and still confined to the ovary, the five-year survival rate is about 92%. When found after it has spread to distant sites, that number drops to roughly 31%.
Where Ovarian Cancer Starts
The ovaries contain three main cell types, and cancer can arise from any of them. Epithelial tumors, which develop from the thin layer of tissue covering the ovary, make up the vast majority of cases and cause most ovarian cancer deaths. Germ cell tumors start in the egg-producing cells and tend to occur in younger women. Stromal tumors grow in the hormone-producing tissue of the ovary and are the rarest of the three.
For decades, scientists assumed all epithelial ovarian cancers originated on the surface of the ovary itself. More recent evidence points to the fallopian tubes as the actual starting point for a large share of the most aggressive subtype, called high-grade serous carcinoma. This discovery has changed how some preventive surgeries are approached: removing the fallopian tubes may reduce risk even when the ovaries are left in place.
Symptoms and How to Recognize Them
Ovarian cancer symptoms overlap heavily with common digestive complaints, which is why the disease is so often caught late. The hallmark cluster includes persistent bloating, a noticeable increase in abdominal size, and urinary urgency, sometimes alongside constipation. In one study comparing women with ovarian cancer to those visiting primary care clinics, that specific combination of symptoms appeared in 43% of cancer patients but only 8% of the general clinic population.
The key distinction is frequency and recency. Women with ovarian cancer typically experience these symptoms 20 to 30 times per month, and the problems tend to be relatively new, with a median duration of only three to four months. By contrast, people with irritable bowel syndrome usually report similar symptoms stretching back 12 to 24 months or longer. If bloating, pelvic pressure, or urinary changes are happening nearly every day and started within the past few months, that pattern deserves medical attention.
Other symptoms can include feeling full quickly when eating, unexplained fatigue, back pain, and changes in bowel habits. None of these alone point to ovarian cancer, but the combination and the timeline matter.
Risk Factors
Age is the single biggest risk factor. Most ovarian cancers are diagnosed in women over 50, and the risk climbs with each decade. Family history of ovarian or breast cancer also raises risk significantly, especially when it involves a first-degree relative.
Inherited gene changes in BRCA1 and BRCA2 carry the most dramatic increase. Women with a harmful BRCA1 change have a 39% to 58% lifetime risk of developing ovarian cancer. For BRCA2, the range is 13% to 29%. In the general population, the lifetime risk sits around 1.2%, so these mutations represent a 10- to nearly 50-fold increase depending on the gene involved.
Other factors that raise risk include never having been pregnant, starting menstruation early, reaching menopause late, and using hormone replacement therapy for extended periods. Factors that lower risk include having used oral contraceptives, having had one or more pregnancies, and breastfeeding.
How Ovarian Cancer Is Diagnosed
There is no reliable screening test for ovarian cancer in the general population. A blood test measuring a protein called CA-125 is sometimes used, but it is not accurate enough for routine screening. Many non-cancerous conditions can raise CA-125 levels, including endometriosis, uterine fibroids, liver disease, pelvic inflammatory disease, menstruation, and pregnancy. At the same time, some women with ovarian cancer have normal CA-125 levels. Large studies have found no evidence that screening with CA-125 reduces the chance of dying from the disease.
When ovarian cancer is suspected, the diagnostic workup typically starts with a pelvic exam and transvaginal ultrasound. Imaging helps distinguish simple fluid-filled cysts from more complex masses. In premenopausal women, most ovarian cysts are functional (formed during normal ovulation) and resolve on their own. In postmenopausal women, the ovaries should no longer be forming cysts, so any new mass raises more concern. A CA-125 blood test may be ordered alongside imaging to add context, but ultimately a tissue sample obtained during surgery is needed to confirm the diagnosis.
Stages of Ovarian Cancer
Ovarian cancer is staged using a system that ranges from I to IV, based on how far the disease has spread at the time of diagnosis.
- Stage I: The tumor is confined to one or both ovaries. The capsule around the ovary is intact, and cancer cells have not spread to surrounding fluid or tissues.
- Stage II: The cancer has spread beyond the ovaries but remains within the pelvis, potentially involving the uterus, fallopian tubes, or other pelvic tissues.
- Stage III: The cancer has spread beyond the pelvis into the abdominal lining or to nearby lymph nodes. This is the most common stage at diagnosis for epithelial ovarian cancer.
- Stage IV: The cancer has reached distant organs. This can mean fluid around the lungs containing cancer cells, or tumors in the liver, spleen, or organs outside the abdomen entirely.
Because symptoms are subtle and there is no effective screening, only a minority of cases are caught at Stage I. That gap between early and late detection is the central challenge of this disease.
Survival by Stage
Five-year relative survival rates from the SEER database, based on data from 2016 to 2022, give a clear picture of how much stage matters:
- Localized (confined to the ovary): 91.9%
- Regional (spread to nearby structures or lymph nodes): 70.1%
- Distant (spread to distant organs): 31.5%
These numbers represent averages across all ovarian cancer types and all age groups. Individual prognosis depends on the specific tumor type, the patient’s overall health, and how the cancer responds to treatment. Newer targeted therapies are improving outcomes for some subgroups, particularly those with certain genetic profiles.
Treatment: Surgery and Chemotherapy
Standard treatment for ovarian cancer involves two main components: surgery and chemotherapy, usually in that order. The goal of surgery is to remove as much visible tumor as possible, a process called debulking. The extent of surgery depends on how far the cancer has spread but often includes removing both ovaries, the fallopian tubes, the uterus, and any visible tumor deposits on the abdominal lining. How much tumor the surgeon is able to remove is one of the strongest predictors of long-term outcome.
After surgery, most patients receive platinum-based chemotherapy. The current standard regimen pairs a platinum drug with a second agent that interferes with cell division. This combination became the standard of care after multiple large trials showed it outperformed older drug pairings. Treatment is delivered in cycles over several months, and the side effects (fatigue, nausea, hair loss, lowered blood counts) vary in severity from person to person. In some cases where initial surgery isn’t feasible, chemotherapy is given first to shrink the tumor before operating.
Targeted Therapy for Specific Genetic Profiles
A class of drugs called PARP inhibitors has significantly changed how ovarian cancer is managed after initial treatment. These drugs work by blocking a repair mechanism that cancer cells rely on to fix damaged DNA. When that repair pathway is shut down, cancer cells with existing DNA repair deficiencies accumulate so much damage that they die. Normal cells, which have backup repair systems, are largely spared.
PARP inhibitors are most effective in patients whose tumors carry BRCA1 or BRCA2 mutations or test positive for a broader category of DNA repair problems known as homologous recombination deficiency. In clinical trials, patients with these genetic markers who received a PARP inhibitor as maintenance therapy after chemotherapy saw dramatic reductions in the risk of their cancer progressing. For patients with BRCA mutations specifically, one major trial showed a 69% reduction in the risk of disease progression compared to standard treatment alone.
Biomarker testing has become a critical step in ovarian cancer care. Knowing whether a tumor has a BRCA mutation or other DNA repair deficiency directly determines which maintenance therapies are likely to provide the most benefit. This testing is now routine at most cancer centers.