Can an Ovarian Cyst Be Cancerous?

Ovarian cysts, fluid-filled sacs that develop in and on the ovaries, can be cancerous, but the likelihood of that depends on when in a woman’s life they occur.

Before menopause, or the cessation of menstruation, ovarian cysts are less likely to be cancerous. They are more likely the result of normal ovulation and other causes. After menopause, new cysts are somewhat more likely to be cancerous, though the vast majority will be harmless (benign).

If ovarian cancer is suspected, a healthcare provider will perform a pelvic exam and run some tests. Treatment commonly involves surgery, but may include chemotherapy, radiation, hormone therapy, and other therapies.

This article offers you an overview of different types of ovarian cysts and when they might be cause for concern. It also further explains how ovarian cancer may be diagnosed and treated.

Types of Ovarian Cysts

In most women, cancer is a rare cause of an ovarian cyst. There are many other possible reasons, especially before you reach menopause. The risk of ovarian cancer tends to rise with age, with most cases occurring after menopause.

Before menopause, common types of ovarian cysts include:

• Follicle cysts: Also called functional cysts, these can develop when a follicle does not rupture and release an egg during ovulation.
• Noncancerous growths: These include fibromas, which are made of connective tissue.
• Corpus luteum cysts: A cyst can develop as a temporary structure (the corpus luteum) is being formed after ovulation. These cysts are common and benign. They typically go away on their own without treatment.
• Dermoid cysts: Also known as teratomas, these cysts are most often seen in women between ages 20 and 40. They are caused when fetal skin cells become trapped in ovarian tissues. The vast majority are benign.
• Cystadenomas: These cysts develop from cells on the outer surface of the ovaries. They are among the more common ovarian tumors that occur here and are, in most cases, benign.
• Endometriomas: These cysts may arise when you have endometriosis, a condition in which tissue lining the uterus spreads outside of it. It is rare for this type of cyst to be cancerous.

Other health conditions that may lead to ovarian cysts before menopause include:

• Pregnancy: An ovarian cyst can develop in early pregnancy until the placenta is fully formed. In some cases, the benign cyst may persist until later in the pregnancy.
• Severe pelvic infection: Ovarian cysts that form during a severe pelvic infection are caused by a build-up of pus in ovarian tissue. Antibiotics may be needed to treat the infection.
• Polycystic ovary syndrome (PCOS): PCOS is a hormonal disorder that may affect women in their childbearing years. It causes the ovaries to enlarge and multiple cysts to form on the outer edges.
• Ovarian cancer: Before menopause, fewer than 1% of new growths on or in an ovary will turn out to be cancer.

The picture is slightly different for women after menopause. Common causes of ovarian cysts in these women include:

• Cystic lesions: Ovarian cysts of less than 1 centimeter (0.4 inches) in size are common but the vast majority will be benign.
• Serous cystadenoma: This benign condition is common in late postmenopausal women, and causes fluid-filled cysts.
• Ovarian cancer: Around 90% of ovarian cancers occur in women over 45. Some 80% occur in women over 50. The vast majority are diagnosed between the ages of 60 and 64.

Risk Factors

There are certain features of an ovarian cyst that make it more likely to be cancerous. There also are risk factors that can increase a woman’s odds of a malignancy.

Ovarian cancer is more likely in women with:

• A family history of ovarian, gastrointestinal, or breast cancer, especially in first-degree relatives (like parents or siblings) who had cancer at an early age
• A previous history of breast or gastrointestinal cancer (e.g., stomach, liver, pancreas, intestine)
• A genetic predisposition for ovarian cancer (indicated by mutations of the BRCA1 and BRCA2 genes)
• An ovarian cyst over 5 centimeters (2 inches) that is irregular in shape and/or has solid areas
• Multiple cysts on both ovaries
• Ascites (a fluid buildup in the pelvis or abdomen)

Older age also plays a role, but this does not mean premenopausal women are not at risk. At age 40, roughly one in 870 (0.1%) are at risk of developing ovarian cancer in the next 10 years. The lifetime risk through age 80 and up is 1.3%.

Symptoms of Cancerous Ovarian Cysts

Symptoms alone cannot indicate whether an ovarian cyst means cancer or is benign.

Many women with ovarian cancer will have few if any symptoms, particularly in the early stages. If there are symptoms, they often are non-specific. It’s easy to think they are caused by less serious conditions.

Women with ovarian cancer will often have vague abdominal symptoms. They include:

• Persistent abdominal swelling
• A persistent feeling of fullness
• Loss of appetite
• Pelvic or abdominal pain
• An increased need to urinate

Where these symptoms become more relevant is in women over 50. Such symptoms seen after menopause, along with a significant family history of breast or ovarian cancer, strongly indicate a need for further testing.

Diagnosis

Most ovarian cysts are found during an annual pelvic exam.

If one is found and ovarian cancer is suspected, the doctor will start the diagnosis by reviewing your family history, medical history, symptoms, and risk factors.

Women at high risk of ovarian cancer or with an abnormal pelvic exam will commonly undergo a series of tests. They include:

• Transvaginal ultrasound: This involves the insertion of a wand-like device into the vagina. It can image tissues using sound waves. This is the single most effective way of imaging and characterizing ovarian cysts.
• CA-125 test: This blood test measures the level of a protein called CA-125. It is secreted by ovarian cancer cells and useful in supporting a cancer diagnosis in high-risk women. However, CA-125 levels can also rise during menstruation, in women with uterine fibroids, and in those with other types of cancers, such as endometrial and peritoneal cancer.
• Magnetic resonance imaging (MRI): This imaging technology uses powerful radio and magnetic waves to create highly detailed images of soft tissue. It can help map the structure of an ovarian cyst.

Computed tomography (CT) scans tend to be less sensitive than MRIs and are less useful in the initial diagnosis of ovarian cancer. Similarly, blood tests used to evaluate and monitor for other cancers, such as the carcinoembryonic antigen (CEA) test, may be less helpful for ovarian cancer.

When cancer is suspected, a healthcare provider will often perform a biopsy to obtain a tissue sample that can be evaluated in the lab. However, that’s not typically the case with ovarian cancer, especially in postmenopausal women. This is due to concern that the biopsy itself may spread any cancer cells.

Instead, a definitive diagnosis is achieved through surgery. Common procedures include:

• Pelvic laparoscopy: This minimally invasive procedure involves inserting a narrow scope with an attached camera through a tiny incision in the abdomen in order to view the reproductive organs. A tissue sample may be taken during the procedure in order to diagnose ovarian cancer.
• Laparotomy: This more extensive procedure may be necessary if the provider needs better access to view the cyst and the surrounding abdominal organs. In most cases, the procedure is similar to the laparoscopy, but with more incisions needed to see inside the abdomen and to take a tissue sample.
  

How Ovarian Cancer Is Treated

Most women diagnosed with ovarian cancer will have some form of surgery to remove the tumor. Depending on the type and stage of ovarian cancer, other forms of treatment may be needed before and/or after their procedure.

Surgery

The main goal of ovarian cancer surgery is to remove as much of the tumor as possible. This is called debulking. It may involve removing nearby tissue, including parts of the colon, small intestine, liver, spleen, bladder, or pancreas.

Many women with ovarian cancer will undergo a hysterectomy with bilateral salpingo-oophorectomy. This means the uterus, both ovaries, and both fallopian tubes are removed.

Chemotherapy

Following surgery, powerful chemotherapy drugs are the mainstay of aggressive treatment plans for most women. They aim to kill fast-growing cells, including those forming a tumor.

This usually involves platinum-based drugs like cisplatin or carboplatin. They are combined with another type of drug called a taxane, which includes Taxol (paclitaxel) and Taxotere (docetaxel).

Other drugs may be added to chemotherapy. They are usually given through an IV every three to four weeks for three to six cycles.

Targeted Therapy

Targeted therapies help to kill cancer cells but cause minimal harm to normal tissues. Their use is based on specific genetic mutations, or changes, that are associated with ovarian cancer.

A link between BRCA genes and an elevated risk of ovarian cancer is well-established. Other research suggests ovarian cancer risk may be linked to the MSH6, RAD51C, TP53, and ATM genes.

Targeted therapy drugs, by themselves or within a treatment plan that includes chemotherapy, may be used when such changes are present.

These drug options, most often used to treat people with BRCA mutations, include:

• Avastin (bevacizumab), given via an infusion into a vein to shrink or slow the growth of a tumor by preventing the formation of new blood cells that nourish them
• PARP inhibitors like Lynparza (olaparib) and Zejula (niraparib), which are taken by mouth and typically used for advanced ovarian cancer

Hormone Therapy

Hormone therapy can treat certain types of ovarian cancer or prevent their return.

These treatments work by blocking the action of estrogen, a hormone that can influence the growth of certain cancers.

Hormone therapy options include:

• Luteinizing hormone (LH), which lowers estrogen levels in premenopausal women
• Aromatase inhibitors like Femara (letrozole) and Aromasin (exemestane) that lower estrogen levels in postmenopausal women
• Tamoxifen, a drug more commonly used in hormone-sensitive breast cancer but one that may be useful in certain advanced ovarian cancers

Radiation

Radiation therapy is less commonly used to treat a primary ovarian tumor. It is more often used to treat areas where cancer has metastasized (spread).

This typically involves external beam radiation therapy (EBRT), in which a narrow beam of ionizing X-ray radiation is directed at cancerous tissues for several weeks.

Brachytherapy, involving the implantation of radioactive seeds into tumors, is rarely used to treat ovarian cancer.

Prognosis

Depending on the type and stage of cancer involved, doctors can generally predict a woman’s long-term outlook (prognosis). This is based on standard five-year survival rates, which estimate the percentage of women who will live for at least five years following diagnosis.

The outlook is largely determined by whether the tumor is confined to one area (localized), affecting nearby tissues (regional), or spread to distant areas (metastasized).

According to the American Cancer Society, the five-year survival rates for women with epithelial ovarian cancer (the most common kind) that has spread beyond the original site are:

• Localized: 93%
• Regional: 75%
• Distant: 31%
  

Summary

Ovarian cysts are quite common in women. Most of the time, these cysts are benign. They do not mean a cancer diagnosis, and some may even resolve on their own. Others are linked to different conditions, such as PCOS. But there is a risk of ovarian cancer associated with these cysts. Though it is rare, that cancer risk increases with age.

Symptoms seen in women age 50 and over become more of a cause for concern. The risk also is higher in people with a family history of cancers that suggest a genetic link to the condition. A healthcare provider can help you to determine what’s causing any cysts and the best course of action for treating the condition.

A Word From Verywell

As scary as it may be to hear that you have an ovarian cyst⁠—or, even more specifically, a pathologic ovarian cyst⁠—be aware the majority are benign. Even so, it is important to have any abnormal growth checked out and regularly monitored in the unlikely event it becomes cancerous.

Even if a cyst turns out to be malignant, early diagnosis almost always will lead to simpler treatments and better outcomes. Ever-improving therapies are likely to extend survival times in the coming years, even among women with advanced ovarian cancer.