Ovarian cancer
Ovarian cancer: Excerpt from Professional Guide to Diseases (Eighth Edition)
Ovarian cancer is one of the leading causes of gynecological deaths in the United States. In women with previously treated breast cancer, metastatic ovarian cancer is more common than cancer at any other site and may be linked to mutations in the BRCA1 or BRCA2 gene.
The prognosis varies with the histologic type and stage of the disease but is generally poor because ovarian tumors produce few early signs and are usually advanced at diagnosis. Although about 46% of women with ovarian cancer survive for 5 years, the overall survival rate hasn't improved significantly.
Three main types of ovarian cancer exist:
❑Primary epithelial tumors account for 90% of all ovarian cancers and include serous cystadenocarcinoma, mucinous cystadenocarcinoma, and endometrioid and mesonephric malignancies. Serous cystadenocarcinoma is the most common type and accounts for 50% of all cases.
❑Germ cell tumors include endodermal sinus malignancies, 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), granulosa-theca cell tumors, and the rare arrhenoblastomas (which produce androgen and have virilizing effects).
Causes and incidence
Exactly what causes ovarian cancer isn't known, but the greatest number of cases occurs in the fifth decade of life. However, it can occur during childhood. Other contributing factors include infertility; nulliparity; familial tendency; ovarian dysfunction; irregular menses; and possible exposure to asbestos, talc, and industrial pollutants.
Primary epithelial tumors arise in the ovarian surface epithelium; germ cell tumors, in the ovum itself; 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. Generally, extraperitoneal spread is through the diaphragm into the chest cavity, which may cause pleural effusions. Other metastasis is rare.
Signs and symptoms
Typically, symptoms vary with the size of the tumor. An ovary may grow to considerable size before it produces overt symptoms. Occasionally, in the early stages, ovarian cancer causes vague abdominal discomfort, dyspepsia, and other mild GI disturbances. As it progresses, it causes urinary frequency, constipation, pelvic discomfort, distention, and weight loss. Tumor rupture, torsion, or infection may cause pain, which, in young patients, may mimic appendicitis. Granulosa cell tumors have feminizing effects (such as bleeding between periods in premenopausal women); conversely, arrhenoblastomas have virilizing effects. Advanced ovarian cancer causes ascites, rarely postmenopausal bleeding and pain, and symptoms relating to metastatic sites (most commonly pleural effusions).
Diagnosis
Diagnosis of ovarian cancer requires clinical evaluation, complete patient history, surgical exploration, and histologic studies. Preoperative evaluation includes a complete physical examination, including pelvic examination with Papanicolaou smear (positive in only a small number of women with ovarian cancer) and the following special tests:
❑abdominal ultrasonography, computed tomography scan, or X-ray (may delineate tumor size)
❑ complete blood count, blood chemistries, and electrocardiogram
❑ excretory urography for information on renal function and possible urinary tract anomalies or obstruction
❑ chest X-ray for distant metastasis and pleural effusions
❑ barium enema (especially in patients with GI symptoms) to reveal obstruction and size of tumor
❑ lymphangiography to show lymph node involvement
❑ mammography to rule out primary breast cancer
❑ liver function studies or a liver scan in patients with ascites
❑ ascites fluid aspiration for identification of typical cells by cytology
❑ laboratory tumor marker studies, such as Ca-125, carcinoembryonic antigen, and human chorionic gonadotropin.
Despite extensive testing, accurate diagnosis and staging are impossible without exploratory laparotomy, including lymph node evaluation and tumor resection. (See Staging ovarian cancer.)
Treatment
According to the staging of the disease and the patient's age, treatment of ovarian cancer requires varying combinations of surgery, chemotherapy and, in some cases, radiation.
Occasionally, in girls or young women with a unilateral encapsulated tumor who wish to maintain fertility, the following conservative approach may be appropriate:
❑resection of the involved ovary
❑biopsies of the omentum and the uninvolved ovary
❑peritoneal washings for cytologic examination of pelvic fluid
❑careful follow-up, including periodic chest X-rays to rule out lung metastasis.
Ovarian cancer usually requires more aggressive treatment, including total abdominal hysterectomy and bilateral salpingo-oophorectomy with tumor resection, omentectomy, appendectomy, lymph node biopsies with lymphadenectomy, tissue biopsies, and peritoneal washings. Complete tumor resection is impossible if the tumor has matted around other organs or if it involves organs that can't be resected. Bilateral salpingo-oophorectomy in a prepubertal girl necessitates hormone replacement therapy, beginning at puberty, to induce the development of secondary sex characteristics.
Chemotherapy extends survival time in most ovarian cancer patients, but it's largely palliative in advanced disease. However, prolonged remissions are being achieved in some patients.
Chemotherapeutic drugs useful in ovarian cancer include carboplatin, docetaxel, cyclophosphamide, doxorubicin, paclitaxel, cisplatin, and topotecan. These drugs are usually given in combination and they may be administered intraperitoneally.
Radiation therapy generally isn't used for ovarian cancer because the resulting myelosuppression would limit the effectiveness of chemotherapy.
Radioisotopes have been used as adjuvant therapy, but they cause small-bowel obstructions and stenosis.
Special considerations
Because the treatment of ovarian cancer varies widely, so must the patient care plan.
Before surgery:
❑Thoroughly explain all preoperative tests, the expected course of treatment, and surgical and postoperative procedures.
❑Reinforce what the surgeon has told the patient about the surgical procedures listed in the surgical consent form. Explain that this form lists multiple procedures because the extent of the surgery can only be determined after the surgery itself has begun.
❑In premenopausal women, explain that bilateral salpingo-oophorectomy artificially induces early menopause, so they may experience hot flashes, headaches, palpitations, insomnia, depression, and excessive perspiration.
After surgery:
❑Monitor vital signs frequently, and check I.V. fluids often. Monitor intake and output, while maintaining good catheter care. Check the dressing regularly for excessive drainage or bleeding, and watch for signs of infection.
❑Provide abdominal support, and watch for abdominal distention. Encourage coughing and deep breathing. Reposition the patient often, and encourage her to walk shortly after surgery.
❑Monitor and treat adverse effects of radiation and chemotherapy.
❑Provide psychological support for the patient and her family. Encourage open communication, while discouraging overcompensation or “smothering” of the patient by her family. If the patient is a young woman who grieves for her lost ability to bear children, help her (and her family) overcome feelings that “there's nothing else to live for.”
PEDIATRIC TIP If the patient is a child, find out whether her parents have told her she has cancer, and deal with her questions accordingly. Also, enlist the help of a social worker, chaplain, and other members of the health care team for additional supportive care. Pictures
Book Source Details
- Book Title: Professional Guide to Diseases (Eighth Edition)
- Author(s): Springhouse
- Year of Publication: 2005
- Copyright Details: Professional Guide to Diseases (Eighth Edition), Copyright © 2005 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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