Ovarian epithelial cancer – Diagnostics – Overview of Information and Clinical Research

Diagnosing ovarian epithelial cancer can be challenging because the disease often develops quietly, without obvious warning signs in its earliest stages. Understanding when to seek medical evaluation, what tests doctors use to identify the disease, and how patients are assessed for clinical trials is crucial for anyone concerned about this cancer or supporting someone facing a diagnosis.

Introduction: Who Should Undergo Diagnostics

Ovarian epithelial cancer is the most common form of ovarian cancer, accounting for about 90% of all ovarian cancer cases. This type of cancer develops in the thin layer of tissue covering the outside of the ovaries, but it can also begin in the lining of the fallopian tubes or in the peritoneum, which is the tissue that lines the abdominal cavity.^[1] Because these cancers grow in similar ways and behave alike, doctors often group them together and treat them using the same approaches.^[3]

One of the biggest challenges with epithelial ovarian cancer is that it rarely causes noticeable symptoms in its early stages. Most people don’t realize anything is wrong until the cancer has already spread beyond the ovaries. In fact, nearly 70% of high-grade serous ovarian cancer cases—the most common and aggressive subtype—are diagnosed at stage 3 or 4, meaning the cancer has already reached nearby organs or lymph nodes.^[1] This late detection is a major reason why ovarian cancer has such high mortality rates compared to other gynecologic cancers.^[2]

Women over the age of 65 who have gone through menopause are at the highest risk for developing ovarian epithelial cancer. More than half of all diagnoses occur in this age group.^[17] However, younger women can also develop the disease, particularly if they have certain risk factors. Anyone with a family history of ovarian cancer, especially in a mother, sister, or daughter, faces an increased risk.^[3] People who carry inherited mutations in genes called BRCA1 and BRCA2 are at significantly higher risk, with lifetime ovarian cancer risks ranging from 17% to 40% depending on which gene is affected.^[7]

Women who have had breast cancer or colon cancer also face a higher likelihood of developing ovarian cancer. Other risk factors include having endometriosis, taking hormone therapy after menopause, being obese, and being taller than average.^[7] Women with these risk factors should discuss their concerns with their gynecologist and consider more frequent check-ups.

⚠️ Important

Unfortunately, there are currently no screening tests proven to improve early detection and outcomes for ovarian cancer. Regular pelvic exams and awareness of symptoms remain the best tools for catching the disease as early as possible.

It’s advisable to seek medical evaluation if you experience symptoms that persist and don’t go away on their own. As the cancer progresses and spreads into the peritoneum, fluid often accumulates in the abdomen, leading to noticeable changes. Common symptoms include abdominal pain, bloating, swelling in the abdomen, difficulty eating or feeling full quickly, nausea and vomiting, and pelvic pain.^[1] Less common warning signs include changes in bowel habits, a strong urge to urinate or urinating more frequently than usual, and vaginal bleeding.^[17]

Many of these symptoms are vague and can easily be mistaken for digestive problems like gas, constipation, or bloating.^[16] This is why ovarian cancer is sometimes called a “silent” disease—it doesn’t announce itself loudly. However, if these symptoms are new for you, happen frequently, and don’t improve after a few weeks, it’s important to see your doctor. Early consultation can make a significant difference, even though the symptoms themselves are not specific to ovarian cancer.

Women who know they have a family history of ovarian or breast cancer, or who have tested positive for BRCA gene mutations, may want to discuss preventive strategies with their healthcare provider. Some women at very high risk choose to undergo surgery to remove their ovaries and fallopian tubes as a way to reduce their cancer risk, though this is a major decision that requires careful consideration.^[3]

Diagnostic Methods

When ovarian epithelial cancer is suspected, doctors use a combination of physical examinations, imaging tests, blood tests, and tissue analysis to confirm the diagnosis and understand how far the cancer has spread. No single test can definitively diagnose ovarian cancer on its own, so doctors rely on multiple approaches to build a complete picture.

Physical Examination

The diagnostic process typically begins with a thorough physical examination and a review of the patient’s medical history. The doctor will ask about symptoms, risk factors, and family history of cancer. A pelvic exam is a key part of this initial assessment. During a pelvic exam, the doctor feels the ovaries and surrounding organs to check for abnormal areas, lumps, or signs of disease.^[6] While a pelvic exam can detect some abnormalities, it cannot definitively diagnose cancer. Ovarian tumors, especially in early stages, may not be large enough to feel during a physical exam.

Imaging Tests

Imaging tests are essential for seeing inside the body and identifying any suspicious masses or growths. Several types of imaging may be used:

Ultrasound and transvaginal ultrasound are often the first imaging tests ordered. An ultrasound uses sound waves to create pictures of the ovaries and surrounding structures. A transvaginal ultrasound involves inserting a small probe into the vagina to get a closer, clearer view of the ovaries. These tests can help determine the size and shape of any masses and whether they appear solid or filled with fluid.^[6]
CT scans (computed tomography scans) use X-rays and computer technology to create detailed cross-sectional images of the abdomen and pelvis. CT scans can show whether cancer has spread to other organs, lymph nodes, or tissues.^[6]
MRI scans (magnetic resonance imaging) use magnets and radio waves to produce detailed images of soft tissues. MRI may be used when doctors need more detailed information about a mass or when CT images are unclear.^[6]
PET scans (positron emission tomography) can help detect cancer that has spread to distant parts of the body. PET scans involve injecting a small amount of radioactive sugar into the bloodstream, which cancer cells absorb more readily than normal cells, making them visible on the scan.^[6]
Chest X-rays may be performed to check whether cancer has spread to the lungs.^[6]

Imaging tests help doctors see where tumors are located and how large they are, but they cannot confirm that a mass is cancerous. For that, doctors need to examine cells or tissue under a microscope.

Blood Tests

A blood test called the CA-125 assay is commonly used when ovarian cancer is suspected. CA-125 is a protein that is often elevated in the blood of women with ovarian cancer.^[6] However, this test is not perfect. CA-125 levels can be elevated for reasons other than cancer, such as endometriosis, pelvic inflammatory disease, or even menstruation. Additionally, not all women with ovarian cancer have elevated CA-125 levels, especially in early stages. Therefore, the CA-125 test is usually used in combination with other tests rather than on its own.

Other blood tests may be performed to assess overall health and organ function, particularly if surgery or chemotherapy is being considered.

Biopsy and Tissue Diagnosis

The only way to definitively diagnose ovarian cancer is through a biopsy, which involves removing a sample of cells or tissue from the affected area and examining it under a microscope. In many cases, the biopsy is performed during surgery to remove the tumor.^[6] Surgeons may remove the entire ovary or a portion of the suspicious tissue, which is then sent to a pathologist for analysis.

Pathologists examine the cells to determine whether they are cancerous and, if so, what type of epithelial ovarian cancer is present. There are several subtypes of epithelial ovarian cancer, including high-grade serous carcinoma, low-grade serous carcinoma, endometrioid carcinoma, mucinous carcinoma, and clear cell carcinoma.^[1] Each subtype has different characteristics, growth patterns, and responses to treatment, so accurate identification is crucial.

The pathologist also assigns a grade to the cancer, which describes how abnormal the cells look under the microscope. Grade 1 cells look similar to normal tissue and tend to grow slowly. Grade 3 cells look very different from normal tissue and are more aggressive.^[7]

Staging

Once ovarian cancer is diagnosed, doctors need to determine the stage of the disease—that is, how far it has spread. Staging helps guide treatment decisions and provides information about prognosis. Ovarian cancer is staged from 1 to 4:

Stage 1: Cancer is confined to one or both ovaries.
Stage 2: Cancer has spread to nearby pelvic structures, such as the uterus or fallopian tubes.
Stage 3: Cancer has spread to the lining of the abdomen (peritoneum) or to lymph nodes.
Stage 4: Cancer has spread to distant organs, such as the lungs or liver.

Staging is typically completed during surgery, when doctors can directly see the extent of cancer spread and take tissue samples from different areas of the abdomen. Imaging tests and blood tests also contribute to staging information.^[2]

⚠️ Important

The stage and grade of ovarian cancer, along with the specific subtype, are critical factors that affect treatment options and prognosis. Advanced-stage cancers are more difficult to treat, but new therapies and clinical trials are offering hope for improved outcomes.

Genetic Testing

Because up to 20% of ovarian cancers are linked to inherited gene mutations, doctors often recommend genetic testing for women diagnosed with ovarian cancer.^[8] This testing looks for mutations in genes like BRCA1, BRCA2, and others associated with hereditary cancer syndromes. Knowing whether a patient carries these mutations can influence treatment decisions, particularly regarding newer targeted therapies. It also provides important information for family members, who may want to undergo genetic counseling and testing themselves.

Diagnostics for Clinical Trial Qualification

Clinical trials are research studies that test new treatments, diagnostic methods, or preventive strategies. Many women with ovarian epithelial cancer choose to participate in clinical trials to access cutting-edge therapies that are not yet widely available. However, not everyone is eligible for every clinical trial. Trials have specific entry criteria, and diagnostic tests are used to determine whether a patient meets these requirements.

Standard Diagnostic Criteria

Clinical trials typically require participants to have a confirmed diagnosis of ovarian epithelial cancer, often verified through biopsy and pathology reports. The trial protocol may specify the stage, grade, or subtype of cancer that is eligible. For example, a trial testing a new treatment for high-grade serous ovarian cancer may exclude patients with low-grade serous or clear cell carcinomas.

Imaging tests such as CT scans, MRI scans, or PET scans are often required to assess the extent of disease before enrollment. These scans provide baseline measurements of tumor size and location, which can be compared to later scans to determine whether the treatment is working.^[15]

Blood Tests and Biomarkers

Many clinical trials require blood tests to measure specific biomarkers or assess overall health. The CA-125 blood test, for example, may be used as a baseline measurement and monitored throughout the trial to track treatment response. Some trials also test for genetic mutations like BRCA1 or BRCA2, as certain treatments work better in patients with these mutations.^[16]

Trials testing new targeted therapies often require testing for specific proteins or receptors on cancer cells. For instance, a trial involving a drug that targets the folate receptor alpha protein would require patients to have tumors with high levels of this protein.^[12]

Performance Status and Organ Function

Clinical trials also assess whether patients are healthy enough to tolerate the experimental treatment. Doctors evaluate what’s called performance status, which is a measure of how well a person can perform daily activities. Patients who are very weak or ill may not be eligible for certain trials.

Blood tests are used to check the function of vital organs, including the kidneys, liver, and bone marrow. This is important because many cancer treatments can affect these organs, and trials need to ensure that participants can safely receive the treatment being tested.^[2]

Imaging and Response Assessment

Throughout a clinical trial, participants undergo regular imaging tests to monitor how the cancer is responding to treatment. These tests are compared to the baseline images taken before the trial began. Doctors look for changes in tumor size, new growths, or signs that the cancer is spreading. This information helps researchers understand whether the treatment is effective.

Participation in a clinical trial can provide access to promising new therapies and contribute to advancing knowledge about ovarian cancer treatment. Women interested in clinical trials should discuss the option with their oncologist and ask about available studies for which they might be eligible.

Prognosis and Survival Rate

Prognosis

The prognosis for ovarian epithelial cancer depends on several factors, including the stage at which the cancer is diagnosed, the grade and subtype of the cancer, how well the treatment works, and the patient’s overall health and fitness level. Unfortunately, because most ovarian cancers are diagnosed at an advanced stage, the overall outlook can be challenging. Advanced-stage cancers that have spread beyond the ovaries are more difficult to treat and control.^[2]

The subtype of epithelial ovarian cancer also plays an important role in prognosis. High-grade serous carcinoma, the most common subtype, tends to spread quickly and is often diagnosed at stage 3 or 4. However, it generally responds well to chemotherapy, at least initially.^[1] Other subtypes, such as clear cell carcinoma and low-grade serous carcinoma, do not respond as well to standard chemotherapy, which can lead to poorer outcomes, especially in advanced stages.^[4]

Most women with ovarian cancer respond to initial treatment with surgery and chemotherapy, with about 80% achieving a complete response, meaning no visible evidence of disease on scans and normal blood tests.^[16] However, more than 80% of patients experience recurrent disease, meaning the cancer comes back after treatment. With each recurrence, the cancer becomes more difficult to control, and the periods between recurrences tend to shorten over time. Eventually, the cancer may become resistant to chemotherapy.^[16]

Women diagnosed with early-stage ovarian cancer, where the disease is confined to the ovaries, have a much better prognosis. Early detection significantly improves survival rates. However, because ovarian cancer rarely causes symptoms in early stages, only about 20% of cases are caught early.^[16]

Newer treatments, including targeted therapies and immunotherapies, are offering hope for improved outcomes. Drugs called PARP inhibitors, for example, can significantly delay cancer recurrence, especially in patients with BRCA gene mutations.^[12] Clinical trials continue to explore new treatment combinations and strategies that may improve long-term survival.

Survival Rate

Survival rates for ovarian epithelial cancer vary widely depending on the stage at diagnosis. The overall five-year survival rate for ovarian cancer is approximately 50%, meaning that about half of women diagnosed with the disease are alive five years after diagnosis.^[7]

However, survival rates are much higher for women diagnosed at an early stage. When ovarian cancer is detected and treated while still confined to the ovaries, the five-year survival rate can be as high as 93% with aggressive treatment.^[7] This highlights the critical importance of early detection, even though effective screening methods are not yet available.

For women diagnosed with advanced-stage ovarian cancer, the outlook is more challenging. Nearly 70% of high-grade serous ovarian cancers are diagnosed at stage 3 or 4, when the cancer has already spread to nearby organs or lymph nodes.^[1] At these stages, the cancer is more difficult to remove completely with surgery, and recurrence is common. More than 50% of women with advanced ovarian cancer die from the disease within five years of diagnosis.^[16]

It’s important to remember that survival statistics are based on large groups of people and represent averages. Individual outcomes can vary widely depending on many factors, including the specific characteristics of the cancer, the patient’s overall health, and how well the cancer responds to treatment. Advances in treatment, including new targeted therapies and participation in clinical trials, are helping to improve survival rates and quality of life for many women with ovarian cancer.