Ovarian Epithelial Cancer

Epithelial ovarian cancer is the most common and deadliest form of ovarian cancer, often diagnosed at advanced stages when it has already spread beyond the ovaries. This disease can be difficult to detect early because symptoms are often subtle or mistaken for less serious conditions, making awareness and regular medical checkups essential.

Table of contents

• What is Ovarian Epithelial Cancer?
• Types of Epithelial Ovarian Cancer
• Associated Anatomy
• Related Conditions
• Signs and Symptoms
• Causes and Risk Factors
• Diagnosis and Testing
• Treatment Options
• Outlook and Prognosis
• Living with Ovarian Epithelial Cancer

What is Ovarian Epithelial Cancer?

Ovarian epithelial cancer is the most common type of ovarian cancer, accounting for approximately 85 to 90 percent of all ovarian cancer cases^[2][7]. This cancer develops in the epithelial tissue, which is a thin layer of cells that covers the outside of the ovaries^[1].

Because of their similarities in how they develop and spread, medical experts also classify fallopian tube cancer and primary peritoneal cancer as epithelial ovarian cancers^[1][3]. The cancer may form in the lining of the fallopian tubes or in the peritoneum, which is the tissue that lines the abdominal wall and covers organs in the abdomen^[3]. These three types of cancer form in the same kind of tissue and are treated in the same way^[3].

Experts now believe that many ovarian cancers actually start in cells at the end of the fallopian tubes and then spread to the ovaries^[1][4]. Cancer sometimes begins at the end of the fallopian tube near the ovary and spreads to the ovary, or it may begin in the peritoneum and spread to the ovary^[3].

This type of cancer can be hard to detect because symptoms may not be noticeable in the early stages. Most people receive a diagnosis once the cancer has already spread^[1]. Ovarian cancer is the leading cause of death in women diagnosed with gynecological cancers and the second most common gynecologic malignancy in the United States^[2].

Types of Epithelial Ovarian Cancer

There are several subtypes of epithelial ovarian cancer, each with different characteristics and behaviors^[1][4].

High-grade serous carcinoma (HGSOC) is the most common and aggressive subtype. It accounts for three out of four epithelial ovarian cancers^[1]. Experts believe HGSOC grows slowly at first and starts in the fallopian tubes. Once the cancer reaches the ovaries, it spreads quickly. Nearly 70 percent of cases are stage 3 or 4 at the time of diagnosis, meaning cancer has spread to nearby organs and lymph nodes^[1].

Less common types of epithelial ovarian cancer include:

• Endometrioid carcinoma — This cancer is more common in people who have endometriosis. It affects the lining of the uterus and responds better to chemotherapy than some other types^[1][4].
• Low-grade serous ovarian carcinoma (LGSOC) — This cancer mainly affects people in their mid-forties. It accounts for about 1 in 10 epithelial ovarian cancers. Low-grade carcinomas grow slowly but for a long time. The disease doesn’t respond well to chemotherapy, and surgery may be needed to treat it^[1][4].
• Mucinous carcinoma — These tumors are more distinct and respond well to treatments. They tend to be large, around 8 inches or 20 centimeters, and typically only affect the ovaries^[1][4].
• Clear cell carcinoma — People who are Asian and people with endometriosis are most at risk for this cancer. The disease is often advanced at diagnosis and doesn’t respond well to chemotherapy^[1][4].
• Primary squamous cell carcinoma (SCC) of the ovary — SCC typically develops from noncancerous conditions. It may form from ovarian cysts, endometriosis, or solid growths on the ovaries. It responds well to treatment when caught early^[1].

Associated Anatomy

• Ovaries
• Fallopian tubes
• Peritoneum
• Uterus
• Abdomen

The ovaries are a pair of organs in the female reproductive system. They are located in the pelvis, one on each side of the uterus. Each ovary is about the size and shape of an almond. The ovaries make eggs and female hormones^[3].

The fallopian tubes are a pair of long, slender tubes, one on each side of the uterus. Eggs pass from the ovaries, through the fallopian tubes, to the uterus^[3].

The peritoneum is the tissue that lines the abdominal wall and covers organs in the abdomen^[3].

Related Conditions

Epithelial ovarian cancer is associated with several related conditions: breast cancer, colon cancer, endometriosis, fallopian tube cancer, and primary peritoneal cancer^[3][7].

Signs and Symptoms

Epithelial ovarian cancer rarely causes symptoms in its early stages. Symptoms become more noticeable as the disease progresses^[1]. As the cancer spreads into the peritoneum, fluid accumulates in the abdomen^[1].

Common symptoms include:

• Abdominal pain or swelling
• Bloating
• Difficulty eating or feeling full quickly
• Nausea and vomiting
• Pelvic pain^[1][3]

Less common symptoms include:

• Changes in bowel habits
• Strong urge to urinate or urinating more frequently
• Vaginal bleeding^[1]

If you experience these symptoms and they do not lessen or go away on their own, you should see your doctor so you can be diagnosed and treated^[6].

Causes and Risk Factors

Epithelial ovarian cancers develop for no known reason. Experts believe many ovarian cancers start in cells at the end of the fallopian tubes and then spread to the ovaries^[1].

Cancer starts when something changes in a cell’s DNA and causes it to grow out of control. These changes, called mutations, can make cells grow too fast or stop them from fixing damage^[20].

Several risk factors may increase the chance of developing epithelial ovarian cancer:

Family history and genetics: A history of ovarian cancer within a family, particularly in a person’s mother, sister, or daughter, increases the risk^[3][7]. Some ovarian, fallopian tube, and primary peritoneal cancers are caused by inherited gene mutations. Inherited changes in the BRCA1 or BRCA2 genes are responsible for between 5 and 15 percent of all epithelial ovarian cancers^[7][8]. People with the BRCA1 mutation have a 39 to 40 percent risk, and those with the BRCA2 mutation have a 17 percent risk of developing ovarian cancer^[7].

Age: More than half of ovarian cancer diagnoses occur in people over 65 who have gone through menopause^[1]. Older age is the main risk factor, and the chance of getting cancer increases as people get older^[8].

Previous cancers: The risk of developing epithelial ovarian cancer is higher in women who have had breast cancer or colon cancer^[7].

Other factors: Taking hormone therapy after menopause increases the risk^[7]. Obesity and tall height are also associated with increased risk^[8]. People with endometriosis may be at higher risk for certain types of epithelial ovarian cancer^[8].

Diagnosis and Testing

If epithelial ovarian cancer is suspected, a doctor will begin by reviewing medical history and conducting a thorough physical examination^[6][7]. A pelvic exam will be performed to feel for abnormal areas and check for signs of disease^[6].

Imaging tests may be recommended to look inside the body. These include:

• Ultrasound and transvaginal ultrasound
• CT scan (computed tomography scan)
• MRI (magnetic resonance imaging)
• PET scan (positron emission tomography)
• Chest X-ray^[6]

Blood tests may be used to check for signs of cancer. A blood test called CA 125 assay measures a protein that may be elevated in people with ovarian cancer^[6][7].

Biopsy provides a definitive diagnosis. During this procedure, the doctor removes a sample of cells or tissue from the affected area to examine in a laboratory^[6][7]. The biopsy helps determine what the cancer cells look like under a microscope.

The cancer is then staged from 1 to 4 based on how far it has grown and spread. The stage of a cancer tells how far it has grown. The grade describes how the cells look under a microscope — the less developed the cells look, the higher the grade. Higher grade cancers grow more quickly than low grade^[4].

Treatment Options

Treatment for epithelial ovarian cancer typically involves a combination of surgery and chemotherapy^[3][10]. The treatment depends on several factors, including the type of epithelial cancer, the size of the cancer and whether it has spread, how abnormal the cells look under the microscope, and the person’s general health^[4].

Surgery is the primary treatment for epithelial ovarian cancer. The goal is to remove as much of the tumor as possible, a procedure called debulking surgery^[1]. Several surgical options may be used:

• Hysterectomy — removal of the uterus^[6]
• Unilateral or bilateral salpingo-oophorectomy — removal of one or both ovaries and fallopian tubes^[6]
• Omentectomy — removal of the omentum, fatty tissue that covers contents of the abdomen^[6]
• Lymph node biopsy — removal of all or part of a lymph node^[6]

Chemotherapy uses drugs to kill cancer cells. First-line treatment typically includes a combination of a platinum-based drug (usually carboplatin) and a taxane-based drug (usually paclitaxel)^[12]. This treatment leads to a complete response in approximately 80 percent of patients^[16].

Targeted therapies are newer treatments that use drugs to target and attack cancer cells^[12]. These include:

• Monoclonal antibodies — Bevacizumab is a drug that prevents the growth of new blood vessels that tumors need to grow. It may be used with chemotherapy^[12][16]. Mirvetuximab soravtansine is another antibody used for people with ovarian cancer recurrence whose tumors have many folate receptors^[12].
• PARP inhibitors — These drugs block DNA repair, which may cause cancer cells to die. After completion of chemotherapy, patients may be eligible to receive maintenance therapy with PARP inhibitors, which can significantly delay and possibly even prevent disease relapse, particularly in patients whose tumors carry mutations in BRCA1 and BRCA2 genes^[12][16].

Other treatment options may include hormone therapy and radiation therapy, depending on the specific situation^[4][6].

Outlook and Prognosis

The outlook for epithelial ovarian cancer varies depending on many factors, including what treatment has already been given, what treatment can be provided now, how well the treatment works, and the person’s general health and level of fitness^[19].

Although response rates to first-line treatment with carboplatin and paclitaxel are greater than 80 percent, most patients will eventually relapse^[13]. The overall five-year survival rate is about 50 percent. However, early detection can significantly improve outcomes, leading to a survival rate of around 93 percent with aggressive treatment^[7].

More than 80 percent of ovarian cancer patients experience recurrent disease^[16]. Patients who initially respond to treatment but then relapse after a period of six months or more may undergo the same therapy again. However, cancers that have come back cannot usually be cured, though treatment can often control the cancer and relieve symptoms for many months and sometimes years^[19].

The stage at diagnosis is a major factor in prognosis. Only about 20 percent of cases are diagnosed in an early stage, and a later-stage diagnosis comes with more challenges^[22]. Nearly 70 percent of high-grade serous cases are stage 3 or 4 at diagnosis^[1].

Living with Ovarian Epithelial Cancer

An ovarian cancer diagnosis may change every aspect of life, from diet and exercise choices to treatment decisions and relationships^[22].

Diet and nutrition: When living with ovarian cancer, aim for a balanced diet, especially while undergoing chemotherapy. During treatment, people often experience discomfort and nausea. Eating small snacks and meals throughout the day can prevent nausea from getting worse. Bland foods that are easy on the stomach, such as clear broth, crackers, plain yogurt, and toast, can be helpful. After treatment, good nutrition remains important. Aim for a high volume of fruits and vegetables, along with lean meats such as chicken and fish^[22].

Exercise and physical activity: Cancer treatment side effects include anxiety, fatigue, and insomnia. Exercise is an excellent method of offsetting some of these symptoms^[22]. A recent study found that a healthy lifestyle after ovarian cancer diagnosis, particularly not smoking and being physically active, may help women improve their prognosis. Higher physical activity after diagnosis was associated with better survival^[23].

Smoking: Both former and current smoking before and after diagnosis were significantly associated with reduced survival. Almost half of women who were current smokers before diagnosis reported having stopped smoking by 12 months after diagnosis. Women with ovarian cancer may achieve an improved prognosis by quitting smoking^[23].

Managing symptoms: Advanced cancer and its treatment can cause physical symptoms that can be difficult to cope with. Treatments such as chemotherapy, radiation therapy, or targeted therapy aim to shrink the cancer, control it for as long as possible, reduce symptoms, and help people feel better. It is important to tell your doctor or nurse about any symptoms you experience so they can help you manage them^[19].

Emotional support: Finding out about cancer can be distressing. It’s common to feel uncertain and anxious. Lots of information and support is available for patients, families, and friends. Some people find it helpful to learn more about their cancer and the treatments they might have, as knowing more about the situation can make it easier to cope^[19].

epithelial carcinoma