What are ovarian cancers?

Related conditions:
Abdominal cancer, colon cancer, cancer of the diaphragm, lymphatic cancer, peritoneal cancer, stomach cancer

Definition:

Ovarian cancers result from the development of a malignant tumor in the ovaries and can be divided into three main types. The most common is epithelial ovarian cancer, which originates in the surface cells of an ovary. The second type, germ-cell ovarian cancer, starts in the interior cells of an ovary, where eggs are produced. A third main type, stomal ovarian cancer, begins in the connective tissue cells that hold an ovary together and generate the female hormones estrogen and progesterone.

Risk factors: One of the most important risk factors involved in the development of ovarian cancers is inherited gene mutations. In 2014 the National Cancer Institute reported that based on research published in 2005, the inheritance of mutated breast cancer genes, BRCA1 and BRCA2, is responsible for approximately 15 percent of all ovarian cancers. Other factors include having had breast or colon cancer, having a family history of ovarian cancer, not having given birth, taking fertility drugs, and using hormone replacement therapy after menopause. Age is an important risk factor. According to the American Cancer Society (ACS) in 2014, about half of the women diagnosed with ovarian cancer are sixty-three years old or older. ACS also stated that the cancer is more prevalent among white women than African American women.

Etiology and the disease process: The exact cause of ovarian cancers is still unknown. Some specialists have suggested that ovarian cancer in younger women is related to the tissue-repair process subsequent to ovulation. The formation and division of new cells at the site where an egg is released through a small tear in the ovarian follicle may produce genetic errors. Other specialists believe that the origin of ovarian cancers in younger women is related to the production of abnormal cells associated with the increased hormone levels that occur before and after ovulation.

Ovarian cancers are classified according to the histology of the tumor. According to research published in the Annals of Oncology in 2013, about 90 percent of all cases of malignant ovarian tumors are epithelial ovarian cancers, which are classified by cell type and graded from 1 to 3. Obstetrics and Gynecology reported in 2006 that 2.6 percent of US women diagnosed with ovarian cancers had germ-cell tumors, which develop in the egg-producing cells of the ovary and generally occur in younger women. Another type of ovarian cancer develops in the stomal cells, the tissue that holds the ovary together.

Ovarian cancer cells metastasize by spreading into the naturally occurring fluids in the abdominal cavity. These cells frequently become implanted in other peritoneal structures, particularly the uterus, the intestines, the omentum, and the urinary bladder. New tumor growths often occur in these areas. In rare instances, ovarian cancer cells spread through the bloodstream or lymphatic system to other parts of the body.

Incidence: In 2014 ACS reported that ovarian cancer is the fifth leading cause of cancer-related death in women, and estimates that for women in the United States in 2014, about 21,980 individuals will be newly diagnosed with ovarian cancer and 14,270 will die from the disease. In 2013 the Centers for Disease Control and Prevention (CDC) reported that 19,959 women in the United States were diagnosed with ovarian cancer and 14,572 died from it in 2010. Ovarian cancers are most common in industrialized nations. Statistics released by the US National Cancer Institute (NCI) in 2014 show that, based on data from 2008–10, women in the United States have about a 1.4 percent chance of being diagnosed with ovarian cancer over the course of their lives. NCI also reported in 2014 that an estimated 188,867 women were living with ovarian cancer in the United States in 2011.

Symptoms: In the majority of cases, ovarian cancer produces no symptoms or only mild symptoms until it progresses to an advanced stage. Symptoms include general abdominal discomfort, such as bloating, cramps, pressure, and swelling; nausea, diarrhea, or constipation; frequent urination; loss of appetite or feeling bloated after a light meal; and the loss or gain of weight for no apparent reason. Other symptoms can include fatigue, back pain, pain during sexual intercourse, abnormal bleeding from the vagina, menstrual irregularities, shortness of breath, and fluid around the lungs.

Screening and diagnosis: A medical doctor first evaluates a patient’s medical and family history, then performs, a thorough physical examination of the pelvic region. The presence of any abnormal growths should be further investigated using ultrasound imaging and computed tomography (CT) scans. Ultrasound can detect the difference between healthy tissues, fluid-filled cysts, and tumors. CT scans produce detailed cross-sectional images of regions within the body. In some cases, x-rays of the colon and rectum following a barium enema help identify the presence of ovarian cancers. The level of cancer antigen 125 (CA 125) should be assessed with a blood test; however, this marker identifies only about 10 percent of early ovarian cancers. The amount of four other cancer-related proteins in the blood shows some promise for diagnosing ovarian cancers.

A biopsy must be performed for a definitive diagnosis of ovarian cancer. Biopsies are usually done on tumors removed during surgery, although sometimes they are done during a laparoscopy or using a needle guided by ultrasound or CT scans. If ovarian cancer is present, the stage of the disease is assessed. Staging for ovarian cancer is as follows:

• Stage I: The cancer is limited to one or both ovaries.





• Stage II: The cancer has extended into the pelvic region, such as the uterus or Fallopian tubes.





• Stage III: The cancer has spread outside the pelvis or is limited to the pelvic region but is present in the small intestine, lymph nodes, or omentum.





• Stage IV: The cancer has metastasized to the liver or tissues outside of the peritoneal cavity.

These stages are further broken down into levels of seriousness from A to C.

Treatment and therapy: Depending on the stage of ovarian cancer, surgery is often performed to remove the ovaries, uterine tubes, uterus, omentum, and associated lymph nodes. This process is referred to as surgical debulking. The stage of the disease determines whether additional therapy is needed. Typically, chemotherapy is employed, and if the cancer is localized, radiation therapy is sometimes used. The most effective chemotherapy drugs used in treating ovarian cancers are carboplatin and paclitaxel (Taxol), administered intravenously. The combination reduces cell division in ovarian tumors.

Intraperitoneal therapy, or pumping chemotherapy drugs directly into a patient’s abdomen, extends the lives of ovarian cancer victims by an additional year or more; however, it can cause side effects such as stomach pain, numbness in the extremities, and possible infection. In January 2006, the National Cancer Institute recommended an individualized combination of intravenous and intraperitoneal therapy for ovarian cancer patients. New chemotherapy drugs, vaccines, gene therapy, and immunotherapy treatments are being explored as options for treating ovarian cancers.

Prognosis, prevention, and outcomes: More than 60 percent of ovarian cancer patients are in stage III or IV at the time of diagnosis, so the prognosis is not promising. In 2006 Obstetrics and Gynecology published a study showing that ovarian cancer patients had an overall five-year survival rate of less than 50 percent, with rates varying depending on the stage and specific type of ovarian cancer, as well as other factors. With early diagnosis, aggressive surgery, and chemotherapy, the five-year survival rate is above 90 percent and the long-term survival rate approaches 70 percent. In 2012 Obstetrics and Gynecology reported a five-year survival rate of 89 percent and a ten-year survival rate of 84 percent, both for stage I epithelial ovarian cancer. For germ-cell ovarian cancer, the prognosis is better than for epithelial ovarian cancer.

Eating well, exercising, and properly managing stress help produce good overall health and reduce the risk of developing ovarian cancers. Measures that help prevent ovarian cancer include having children and breast-feeding them, using oral contraceptives (30 percent reduction), and having a tubal ligation. For women who have a high risk of developing ovarian cancers, removal of the ovaries may be the best prevention.

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