Can an Ovarian Cyst Be Cancerous?

Ovarian cysts are fluid-filled sacs that develop in and on the ovaries. They can affect women of all ages and are most often benign. Before menopause, 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 but the vast majority still will be benign.

If ovarian cancer is suspected, a healthcare provider will perform several tests. They may include a pelvic exam, transvaginal ultrasound, and other diagnostic techniques. Treatment commonly will mean surgery, but may include chemotherapy, radiation, hormone therapy, and newer targeted therapies.

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

2:12

Understanding Ovarian Cancer Symptoms, Stages, and Treatment

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 causes of ovarian cysts include:

Ovulation: A "functional cyst" can develop when a follicle does not rupture and release an egg during ovulation. It can also develop as 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.
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 buildup 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.

Endometriosis: This condition occurs when the lining of the uterus (endometrium) extends beyond the uterus. It often causes the formation of cysts called endometrioma, also known as "chocolate cysts."
Noncancerous growths: These include fibromas that are made of connective tissue, and fluid-filled cystadenomas that form on the outside of the ovaries and can become quite large.
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.
Intrauterine fluid accumulation: This is common in late postmenopausal women. It can trigger swelling of the ovaries, along with the formation of ovarian 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 to 64.

Despite the increased incidence of ovarian cancer in postmenopausal women, the lifetime risk is still relatively low. At age 60, a woman's risk of developing ovarian cancer in the next 10 years is about 0.3%. The 10-year risk rises slightly to 0.4% for a woman at age 80. The overall lifetime risk of a woman developing ovarian cancer is 1.3%.

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
A genetic predisposition for ovarian cancer (as 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)

Age also plays a role, but it does not exclude premenopausal women. Roughly one in 870 (0.1%) are at risk of cancer.

Abnormal ovarian cysts often are called pathologic cysts in lab reports. This does not mean that the cyst is cancerous, but simply that it is unusual in its shape, size, or consistency. Most pathologic cysts are benign.

Symptoms

Symptoms alone cannot predict 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 nonspecific. It's easy to think they are caused by less serious conditions.

Women with ovarian cancer often will 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.

Recap

Ovarian cysts rarely lead to a cancer diagnosis in women who have not reached menopause. In most cases, there is another reason for these cysts. The risk of ovarian cancer rises with age, though, and most cases are diagnosed in women who are in their 60s. The risk also is higher for women who have a family history of cancers linked to BRCA1 and BRCA2 genetic mutations.

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.

The evaluation may also involve a rectovaginal exam in which a finger is inserted into the vagina and another into the rectum to get a better sense of the size and consistency of the cyst.

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

Transvaginal ultrasound: This involves the insertion of a wand-like device into the vagina. It can image tissues using sound waves. It 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 to map the structure of an ovarian cyst.

Computed tomography (CT) scans tend to be less sensitive than MRIs. They 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), may be less helpful for ovarian cancer.

When cancer is suspected, a healthcare provider will often perform a biopsy to take a tissue sample and have it evaluated in the lab. That's not typically the case with ovarian cancer, especially in postmenopausal women. This is due to concern that the biopsy itself may spread the cancer cells.

Instead, a definitive diagnosis is done through surgery. Common procedures include the minimally invasive laparoscopy and the more extensive exploratory laparotomy.

During the pelvic laparoscopy, a narrow scope with an attached camera is inserted 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.

A laparotomy 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 take a tissue sample to confirm any cancer.

In the United States, around 5% to 10% of women will undergo surgical evaluation of an ovarian cyst. Of these tests, 13% to 21% of the investigations will reveal cancer.

Treatment

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, either before or after surgery (or both).

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.

If cancer is limited to one ovary, and it is caught in the earliest stage, it may be possible to keep the other ovary and fallopian tube in women who intend to have children. Most women, however, are likely to have both ovaries removed. This is true even if they are younger and hope to become pregnant one day.

Chemotherapy

Following surgery, aggressive chemotherapy is the mainstay of treatment for most women. 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 line, 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. These therapies may be used by themselves or as part of the treatment plan, especially following chemotherapy. Options include:

Avastin (bevacizumab), which can shrink or slow the growth of a tumor by preventing the formation of new blood cells that nourish them
PARP inhibitors like Lynparza (olaparib), Rubraca (rucaparib), and Zejula (niraparib) that are typically used for advanced ovarian cancer

Hormonal Therapy

Hormonal therapy can treat certain types of ovarian cancer or prevent their return. These include hormones and drugs that block the action of estrogen, a female hormone that can influence the growth of certain cancers. 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.

Recap

Treatment for ovarian cancer begins with surgery for most women. The goal is to remove as much of the cancer as possible through a procedure called debulking. In many cases, the reproductive organs also may be removed. Surgery is often followed by chemotherapy. Other options include targeted therapy drugs and hormonal therapy. Radiation is an option too, but it is usually used when the cancer has spread to other sites in the body.

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 localized, regional (affecting nearby tissues), or distant (metastasized).

According to the American Cancer Society, the current five-year survival rate for women with ovarian cancer is:

Localized: 92%
Regional: 76%
Distant: 30%

The outcome of surgery also plays a role in survival rates. Women with an ovarian tumor that is debulked well have a better outlook than women in whom tumor tissues remain.

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.