Ovarian Cancer Information

Ovarian cancer is often called the "silent" killer because many times there are no symptoms until the disease has progressed to an advanced stage. After cancers of the lung, breast, and colon, primary ovarian cancer ranks as the most common cause of cancer death among American women. In women with previously treated breast cancer, metastatic ovarian cancer is more common than cancer of any other organ.

The prognosis varies with the histologic type and staging of the disease. but it's often poor because ovarian tumors are difficult to diagnose and progress rapidly. About 40% of women with ovarian cancer survive for 5 years.

Causes

Environmental and lifestyle factors seem to play a role in ovarian cancer. Women who live in industrialized nations are at greater risk, as are those whose diet is high in saturated fat. Other risk factors include infertility problems or nulliparity, celibacy, exposure to asbestos and talc, a history of breast or uterine cancer, and a family history of ovarian cancer.

Primary epithelial tumors arise in the müllerian epithelium; germ cell tumors in the ovum; and sex cord tumors in the ovarian stroma. Ovarian tumors spread rapidly intraperitoneally by local extension or surface seeding and, occasionally, through the lymphatics and the bloodstream. In most cases, extraperitoneal spread is through the diaphragm into the chest cavity, which may cause pleural effusions. Other metastasis is rare.

There are three main types of ovarian cancer:

• Primary epithelial tumors account for 90% of all ovarian cancers and include serous cystadenocarcinoma, mucinous cystadenocarcinoma, and endometrioid and mesonephric malignant tumors.
• Germ cell tumors include endodermal sinus malignant tumors, embryonal carcinoma (a rare ovarian cancer that appears in children), immature teratomas, and dysgerminoma.
• Sex cord (stromal) tumors include granulosa, cell tumors (which produce estrogen and may have feminizing effects), thecomas, and the rare arrhenoblastomas (which produce androgen and have virilizing effects).

Signs and Symptoms

Early symptoms of ovarian cancer are often mild, making this disease difficult to detect. Some early symptoms may include:

• An unusual feeling of fullness or discomfort in the pelvic region
• Unexplainable indigestion, gas, or bloating that is not relieved with over-the-counter antacids
• Pain during sexual intercourse
• Abnormal bleeding
• Swelling and pain of the abdomen
• Weight loss

Most often these symptoms do not indicate ovarian cancer. However, if you experience them you should discuss them with your clinician.

Diagnostic tests 

Tests ordered to help assess the patient's condition may include a complete blood count, blood chemistries, and electrocardiography.

Exploratory laparotomy, including lymph node evaluation and tumor resection, is required for accurate diagnosis and staging. Abdominal ultrasonography, a computed tomography scan, or X-rays delineate tumor size. Chest X-rays can also help identify distant metastasis and pleural effusions.

Excretory urography provides information on renal function and possible urinary tract obstruction. A barium enema (especially in patients with GI symptoms) may reveal obstruction and tumor size.

Treatment

Surgery is the preferred treatment and is frequently necessary for diagnosis. Studies have shown that surgery performed by a specialist in gynecologic oncology results in a higher rate of cure.

Chemotherapy after surgery extends survival time in most patients but is largely palliative in advanced disease, although prolonged remissions are achieved in some patients. Drugs used include melphalan, chlorambucil, thiotepa, methotrexate, cyclophosphamide, doxorubicin, vincristine, vinblastine, dactinomycin, bleomycin, and cisplatin. These drugs are usually given in combination. Intraperitoneal administration of cisplatin or paclitaxel has slowed disease progression and increased survival.

Radiation therapy isn't commonly used because it causes myelosuppression, which limits the effectiveness of chemotherapy. Radioisotopes have been used as adjuvant therapy but cause small-bowel obstructions and stenosis.

Under investigation, immunotherapy consists of I.V. injection of Corynebacterium parvum or bacille Calmette-Guerin vaccine, lymphokine-activated killer cells, and interleukin-2.

Prevention

Suggested preventive measures include a:

• healthy diet (high in fruits, vegetables, grains, and low in saturated fat)
• birth control pills
• pregnancy and breast feeding
• hysterectomy
• tubal ligation
• removal of ovaries