Ovarian cancer types

In the United States, ovarian cancer is the eighth most common cancer among women, according to the Centers for Disease Control and Prevention (CDC).

While there are more than 30 types of ovarian cancer, all begin in one or both ovaries, or in the nearby fallopian tubes or peritoneum (the tissue that covers organs in the abdomen). Most ovarian cancers are classified by the name of the cell from where the disease originated.

Every ovarian cancer patient is different, and each deserves a treatment plan tailored to her needs and specific diagnosis. That starts with identifying the type of ovarian cancer.

Common types of ovarian cancer

Epithelial ovarian carcinomas: Most epithelial ovarian tumors are benign. However, cancerous epithelial tumors (also known as epithelial ovarian carcinomas) are the most common type of ovarian cancer. According to the American Cancer Society, about 85 to 90 percent of ovarian cancers originate from epithelial cells, which cover the outer surface of the ovary. They commonly spread to the lining and organs of the pelvis and abdomen first before spreading to other parts of the body, such as the lungs and liver. They also may spread to the brain, bones and skin.

There are many subtypes of cancerous epithelial tumors. The most common include those below.

• Serous carcinomas: These make up 52 percent of all epithelial ovarian cancers and are often classified as low-grade serous carcinoma or high-grade carcinoma, depending on how the cancer cells look compared with normal cells. A higher grade means the cancer cells are fast-spreading and may respond best to chemotherapy.
• Endometrioid carcinomas: These tend to grow slowly and cause few symptoms. Although these tumors may be less likely to spread quickly to other areas of the body, they don’t typically respond as well to treatments.
• Mucinous carcinomas: These account for 6 percent of ovarian cancer cases and tend to affect older women. Women younger than 35 rarely are diagnosed with these slow-growing cancers.
• Clear cell carcinomas: This rare ovarian cancer has a good prognosis when caught and treated in the early stages.

Two other types of cancer are similar to epithelial ovarian cancer: primary peritoneal carcinoma and fallopian tube cancer. Because they closely resemble epithelial ovarian cancer, they’re often treated with the same approaches and techniques. Primary peritoneal carcinoma develops in the lining of the pelvis and abdomen. Fallopian tube cancer starts in the fallopian tubes. Both are rare.

Less common types of ovarian cancer

Germ cell tumors: They begin in the reproductive cells, which are in the eggs for women and sperm for men. Germ cell tumors make up less than 2 percent of all ovarian cancers, according to the ACS, and have a high survival rate, with nine out of 10 patients surviving five years after diagnosis.

Some of the most common subtypes of germ cell ovarian tumors are:

• Teratomas—These germ cell tumors are either benign (mature) or cancerous (immature), and their cells may contain different types of tissue, such as hair, muscle and bone. Immature teratomas are rare.
• Dysgerminoma—Though rare, this is the most common germ cell ovarian cancer. Dysgerminomas don’t typically grow or spread quickly, but they may travel to other parts of the body, such as the central nervous system.
• Endodermal sinus tumor (yolk sac tumor) and choriocarcinoma tumors—Endodermal sinus tumors may start in the ovaries or testes, occurring most often in children. Choriocarcinomas may start in the placenta during pregnancy, which are more common, or in the ovaries. Both are extremely rare.

Teenagers and women in their 20s are more likely to develop this type of ovarian cancer. Because germ cell tumors typically affect only one ovary, it’s easier to protect a woman’s fertility during treatment.

Stromal cell tumors: Even less common than ovarian germ cell tumors are ovarian stromal cell tumors (also called sex cord tumors and sex cord-gonadal stromal tumors), representing about 1 percent of all ovarian cancers, according to the ACS. They develop from the stroma tissue cells that produce the female hormones of estrogen and progesterone.

In the case of ovarian cancer, stromal tumors form in the tissues that support the ovaries. Of the cancerous stromal tumor subtypes, most are granulosa cell tumors. Other types include granulosa-theca tumors and Sertoli-Leydig cell tumors.

This type of ovarian cancer is often found in early stages. Vaginal bleeding is one of the most common symptoms. For post-menopausal women in particular, unexpected vaginal bleeding, among other hormonal symptoms, should prompt a conversation with a doctor.

Ovarian sarcoma: Unlike their carcinoma counterparts, ovarian sarcoma tumors develop in the connective tissues of ovarian cells. It hasn’t been studied in-depth and tends to have a poor prognosis compared with other ovarian cancers. The most common symptom is abdominal pain.

Krukenberg tumors: Krukenberg tumors are considered a stage 4 disease—an advanced cancer—because they’re metastatic in nature, meaning the cells easily break away from the original tumor and quickly multiply. This type of tumor may typically be found in the stomach, colon and ovaries. Though it’s often asymptomatic, this tumor may cause gastrointestinal symptoms.

Ovarian cysts: Ovarian cysts are fluid-filled sacs that develop inside the ovary. They’re common during ovulation and often go away on their own without treatment. Although most ovarian cysts are benign, some may develop into cancer.  

Recurrent ovarian cancer

Recurrent or relapsed ovarian cancer occurs when malignant cells reappear after cancer treatments, such as surgery or chemotherapy, have been completed for a period of time. When ovarian cancer recurs, it’s not re-staged. Recurrent ovarian cancer may return at its original location, or it may be found somewhere else in the body.

Ovarian cancer typically recurs when a small number of cancer cells survive the treatment process but are not detected on tests. After treatment, these cancer cells may grow into tumors.

The signs of recurrent ovarian cancer vary from patient to patient. Because ovarian cancer often recurs in the abdomen and pelvis, near the bladder and the intestines, gastrointestinal and urinary symptoms typically develop.

Signs and symptoms of ovarian cancer recurrence may include:

• Persistent abdominal bloating, indigestion or nausea
• Changes in appetite, typically a loss of appetite or feeling full sooner
• Pressure in the pelvis or lower back
• Urge to urinate more frequently
• Changes in bowel movements
• Increased abdominal girth
• Lethargy, fatigue or lack of energy
• Abdominal pain or swelling
• Elevated levels of the CA-125 protein

About 70 percent of patients diagnosed with ovarian cancer experience a recurrence, according to the Ovarian Cancer Research Alliance. The cancer recurrence rate varies by patient, but the risk increases with the cancer’s stage at the time it was originally diagnosed (the more advanced the stage, the higher the risk). Follow-up appointments with an oncologist may help detect cancer relapse early. Routine gynecologic care and annual pelvic exams are recommended to screen for symptoms of relapsed ovarian cancer.