Stage 3 ovarian cancer represents an advanced form of the disease where cancer cells have moved beyond the ovaries to spread into the abdominal cavity or nearby lymph nodes. Understanding this stage, its treatment options, and what to expect can help patients and their families navigate the journey ahead with greater clarity and confidence.

Understanding Stage 3 Ovarian Cancer

Stage 3 ovarian cancer means the disease has spread outside the pelvic area. The cancer may be found in the lining of the abdominal cavity, called the peritoneum, or in the lymph nodes, which are small glands in the back of the abdomen that help fight infection and remove waste from the body. At this stage, the cancer has not yet reached distant organs like the lungs or brain, but it has moved beyond its original location in the ovaries or fallopian tubes.^[1]

Doctors further divide stage 3 into smaller groups to describe exactly where and how much cancer has spread. Stage 3A1 means cancer has reached the lymph nodes behind the organs in the abdomen. The cancer in these nodes can be smaller than 1 centimeter or larger than 1 centimeter, which doctors note as 3A1(i) or 3A1(ii). Stage 3A2 means microscopic amounts of cancer cells are present in the peritoneum and might also be in the lymph nodes. Stage 3B indicates that cancer growths in the peritoneum are visible but measure 2 centimeters or smaller. Stage 3C means the cancer growths are larger than 2 centimeters, and cancer might also be on the surface of the spleen or liver or in the lymph nodes.^[1]

Most people with ovarian cancer—about 60 percent—are diagnosed when the disease has already reached stage 3. This happens because ovarian cancer often develops quietly, without causing noticeable symptoms in its early stages. By the time signs appear, the cancer has usually spread throughout the abdomen.^[6]

Common Symptoms

Ovarian cancer can develop and grow throughout the abdomen before causing clear warning signs, which makes early detection challenging. When symptoms do appear, they can be vague and easy to mistake for other, less serious conditions. This is one reason why many people are diagnosed at an advanced stage.^[4]

Common symptoms of ovarian cancer include pain or discomfort in the pelvic or abdominal area. Many women describe a feeling of bloating that doesn’t go away, even after changing their diet or habits. Changes in eating patterns are also frequent—feeling full very quickly during meals or losing your appetite altogether are both warning signs that shouldn’t be ignored. Some women notice changes in their bowel habits, such as diarrhea or constipation that persists over time.^[4]

Other symptoms can include an increase in the size of the abdomen, which may happen because of fluid buildup called ascites. This fluid accumulation can make the belly feel tight and uncomfortable. Needing to urinate more often than usual is another symptom. Some women also experience abnormal vaginal discharge or bleeding, especially if the bleeding happens outside of the normal menstrual cycle or after menopause.^[4]

If you develop any of these symptoms and they persist for more than a few weeks, it’s important to schedule a visit with a healthcare provider. While these symptoms can be caused by many conditions that are not cancer, it’s always better to get them checked out to be sure.

How Stage 3 Ovarian Cancer Is Diagnosed

Diagnosing ovarian cancer typically begins with a pelvic examination, during which a healthcare provider checks for any abnormal growths or enlarged organs. If ovarian cancer is suspected, additional tests are needed to confirm the diagnosis and determine how far the cancer has spread.^[4]

Imaging tests play a crucial role in diagnosis. A pelvic ultrasound uses sound waves to create pictures of the ovaries and surrounding structures. More detailed imaging, such as a CT scan (computed tomography), MRI (magnetic resonance imaging), or PET scan (positron emission tomography), may be used to see if cancer has spread to other areas of the abdomen or lymph nodes.^[4]

Blood tests are another important tool. Doctors often measure a substance called CA-125, which is a protein that can be elevated when ovarian cancer is present. However, CA-125 levels can also be normal in some women with cancer, and they can be elevated in conditions that are not cancer, such as endometriosis or inflammation. For this reason, blood tests are used alongside other diagnostic methods rather than alone.^[4]

Often, the most accurate way to determine the stage of ovarian cancer is through surgery. During a surgical procedure, the doctor can directly see where the cancer has spread and take tissue samples for examination under a microscope. This process is called surgical staging. In many cases, if abnormal growths are found during surgery, the surgeon will remove them during the same operation.^[1]

Treatment Options for Stage 3 Ovarian Cancer

Treatment for stage 3 ovarian cancer typically involves a combination of surgery and chemotherapy. The specific approach depends on several factors, including where the cancer has spread, whether the surgeon believes all visible cancer can be removed, and the patient’s overall health and personal preferences.^[1]

Surgery

Surgery is often the first step in treating stage 3 ovarian cancer. The specialist surgeon, called a gynaecological oncologist, will remove both ovaries, both fallopian tubes, and the womb, including the cervix. The surgeon will also carefully check the pelvis and abdomen to see where the cancer has spread and whether it is in the lymph nodes.^[1]

The goal of surgery is to remove as much of the cancer as possible. This procedure is called cytoreductive surgery or debulking surgery. In some cases, this might mean removing parts of other organs, such as portions of the intestines, liver, or bladder, if cancer has spread to these areas. Removing all visible cancer during surgery can improve the chances of treatment success and may help patients live longer.^[1]

For some women, surgery might not be possible right away if the cancer has spread too widely or if they are not healthy enough for a major operation. In these situations, doctors may recommend starting with chemotherapy to shrink the tumors first, then performing surgery later, followed by more chemotherapy.^[1]

Chemotherapy

Chemotherapy uses powerful drugs to destroy cancer cells. For stage 3 ovarian cancer, chemotherapy is an essential part of treatment. It can be given after surgery to kill any remaining cancer cells that couldn’t be seen or removed. This is called adjuvant chemotherapy. Alternatively, chemotherapy may be given before surgery to shrink tumors, making them easier to remove. This approach is known as neoadjuvant chemotherapy, and it is followed by surgery and then more chemotherapy afterward.^[1]

The most common chemotherapy regimen for ovarian cancer combines two types of drugs: a platinum-based drug, such as carboplatin or cisplatin, and a taxane drug, such as paclitaxel or docetaxel. These drugs are usually given through a vein, and treatment typically involves several cycles over a period of months.^[14]

In some cases, chemotherapy may be delivered directly into the abdomen during surgery. This technique is called hyperthermic intraperitoneal chemotherapy, or HIPEC. The chemotherapy is heated and circulated inside the abdomen while the patient is still in the operating room. This approach allows high doses of chemotherapy to reach cancer cells in the peritoneum directly.^[1]

Targeted Cancer Drugs

Some patients with stage 3 ovarian cancer may be eligible for treatment with targeted cancer drugs. These medications work differently from chemotherapy by targeting specific features of cancer cells. One example is bevacizumab (Avastin), which works by blocking the growth of new blood vessels that tumors need to survive. This drug may be given along with chemotherapy at first and then continued on its own for up to a year.^[2]

Another type of targeted therapy involves PARP inhibitors. These drugs are especially helpful for women who have certain genetic mutations, such as BRCA1 or BRCA2. PARP inhibitors help prevent cancer cells from repairing their own DNA, which causes the cancer cells to die. Women with these genetic changes may take PARP inhibitors after finishing chemotherapy to help keep the cancer from coming back.^[12]

When Surgery Is Not Possible

If surgery cannot be performed because the cancer has spread too widely or the patient is not well enough for a major operation, chemotherapy can still be given on its own. The goal in these situations is to shrink the cancer as much as possible and slow its growth. Other treatments may be used to relieve symptoms and improve quality of life, such as draining fluid from the abdomen or managing a blocked bowel. Radiation therapy may also be used to relieve symptoms like pain.^[1]

Causes and Risk Factors

The exact cause of ovarian cancer is not fully understood, but researchers know that cancer develops when cells in the ovaries or fallopian tubes begin to grow and divide abnormally and out of control.^[4]

Certain factors can increase a woman’s risk of developing ovarian cancer. Age is one important factor—ovarian cancer is more common in women over the age of 60, and the risk increases as women grow older. Having a family history of ovarian cancer or inheriting gene mutations, such as BRCA1 or BRCA2 mutations or Lynch syndrome, significantly raises the risk. People of Ashkenazi Jewish descent are much more likely to carry BRCA gene mutations, placing them at higher risk.^[4]

Other risk factors include never having been pregnant or having children later in life. Women who are obese also have a higher risk of developing ovarian cancer. Endometriosis, a condition where tissue similar to the lining of the uterus grows outside the uterus, has also been linked to an increased risk.^[4]

Epidemiology

Ovarian cancer accounts for about 1 percent of all new cancer cases in the United States. The lifetime risk of developing ovarian cancer is approximately 1 in 78 for women. Ovarian cancer is slightly more common in Native American and white populations compared to people who are Black, Hispanic, or Asian.^[4]

Estimates indicate that about 21,410 women in the United States received a new diagnosis of ovarian cancer in 2021, and about 60 percent of those diagnosed had stage 3 disease at the time of diagnosis. This high proportion of advanced-stage diagnoses reflects the difficulty of detecting ovarian cancer early, as symptoms often don’t appear until the disease has spread.^[6]

Prevention

There is no certain way to prevent ovarian cancer, but there are steps women can take to reduce their risk. Using oral contraceptives, commonly known as birth control pills, for several years has been shown to lower the risk of ovarian cancer. Pregnancy and breastfeeding also reduce risk, possibly because they reduce the number of times a woman ovulates during her lifetime.^[4]

For women with a strong family history of ovarian or breast cancer, or those who carry BRCA gene mutations, genetic counseling and testing can provide important information. Some women at very high risk may choose to have their ovaries and fallopian tubes removed as a preventive measure once they have finished having children. This surgery, called a prophylactic bilateral salpingo-oophorectomy, significantly reduces the risk of developing ovarian cancer.^[4]

Maintaining a healthy weight, staying physically active, and eating a balanced diet may also contribute to overall health and potentially reduce cancer risk, although the direct impact on ovarian cancer prevention is less clear.

Pathophysiology

Ovarian cancer begins when cells in the ovaries, fallopian tubes, or peritoneum start to grow abnormally and multiply out of control, forming tumors. The most common type of ovarian cancer at stage 3 is high-grade serous cancer. “Serous” refers to the thin membranes, such as the peritoneum, that contain cells which normally secrete a lubricating fluid.^[12]

As the cancer progresses to stage 3, cancer cells break away from the original tumor and spread throughout the abdominal cavity. They often attach to the peritoneum and the surfaces of organs like the intestines, liver, and spleen. Cancer cells can also travel through the lymphatic system to nearby lymph nodes at the back of the abdomen. This spread causes the symptoms many women experience, such as abdominal bloating, pain, and fluid buildup.^[6]

The cancer can interfere with normal bodily functions in several ways. Tumors growing on the bowel can cause changes in bowel habits, including constipation, diarrhea, or even bowel obstruction, which is a serious blockage that prevents food and waste from passing through. Fluid can accumulate in the abdomen, a condition called ascites, which causes swelling and discomfort. Cancer can also affect appetite and digestion, leading to weight loss and nutritional problems.^[7]