Definition


Ovarian cancer is a disease characterized by the uncontrolled and disorganized proliferation of abnormal cells on the surface of the ovary leading to the formation of a malignant tumor. Cells in a malignant tumor have the capacity to spread to other tissues and organs to form secondary tumors, called metastases.

Sources:

Ovarian Cancer. Microsoft Encarta Encyclopedia 2000. Microsoft Corporation, 1999. http://www.encarta.msn.com

What You Need To Know About... Ovarian Cancer. National Cancer Institute. U.S.A. NIH publication No. 00-1561 U.S.A. http://www.cancernet.nci.nih.gov/wyntk_pubs/ovarian.htm#2

 Frequency in the Population


Ovarian cancer accounts for approximately 4% of all cancers affecting women. It is classified 5th in terms of frequency and is the 5th leading cause of cancer deaths among women. About 1 woman in 70 will develop ovarian cancer during her lifetime, whereas 1 woman in 9 will develop breast cancer. Approximately 15 new cases of ovarian cancer per 100 000 women are diagnosed annually in industrialized countries.

Sources:

General Ovarian Cancer Statistics. Ovarian Cancer National Alliance. U.S.A. http://www.ovariancancer.org

Le cancer de l'ovaire. Fédération nationale des centres de lutte contre le cancer. France. http://www.fnclcc.fr/indexcancer.htm

Ovarian Cancer. BC Cancer Agency. Canada. http://www.bccancer.bc.ca/cid/12.shtml#382

Ovarian Cancer in Canada - October 1999. Current events on cancer. Health Canada. http://www.hc-sc.gc.ca/hpb/lcdc/bc/updates/ovar_e.html

What Every Woman Should Know About Ovarian Cancer. National Ovarian Cancer Coalition. U.S.A. http://www.ovarian.org

 Ovarian Cancer Survival Rate


The global survival rate for a woman diagnosed with ovarian cancer is 35% to 47% after 5 years. If the cancer is detected while it is confined to the ovary, the tumor can easily be removed by surgery and 93% of patients will survive at least 5 years. However, due to the fact that this cancer presents few symptoms during its initial stages, only 24% of all cases are detected early. For this reason, this cancer is often called "the whispering cancer" or "the silent killer". When diagnosed in advanced stages, the chance of 5-year survival is only about 25%.

Sources:

General Ovarian Cancer Statistics. Ovarian Cancer National Alliance. U.S.A. http://www.ovariancancer.org

What Every Woman Should Know About Ovarian Cancer. National Ovarian Cancer Coalition. U.S.A. http://www.ovarian.org

 Symptoms


  • General abdominal discomfort and/or pain (gas, indigestion, pressure, swelling, bloating, cramps)
  • Feeling of fullness even after a light meal
  • Unexplained weight gain or loss
  • Loss of appetite
  • Nausea or vomiting, diarrhea, constipation or frequent urination
  • Sense of incomplete evacuation of feces or narrowing of fecal caliber
  • Lump in the abdomen, pelvis or groin
  • Back pain
  • Difficulty in breathing, shortness of breath
  • Cough and/or discomfort in the chest
  • Swelling of the lower body
  • Hormonal imbalance
  • Low grade fever
  • Painful intercourse
  • Unusual fatigue
  • Abnormal vaginal bleeding

Sources:

About Ovarian Cancer. Ovarian Cancer Alliance Canada. http://www.ocac.ca

Ovarian Cancer. BC Cancer Agency. Canada. http://www.bccancer.bc.ca/cid/12.shtml#382

Ovarian Cancer. Microsoft Encarta Encyclopedia 2000. Microsoft Corporation, 1999. http://www.encarta.msn.com

What Every Woman Should Know About Ovarian Cancer. National Ovarian Cancer Coalition. U.S.A. http://www.ovarian.org

What You Need To Know About... Ovarian Cancer. National Cancer Institute. U.S.A. NIH publication No. 00-1561 U.S.A. http://www.cancernet.nci.nih.gov/wyntk_pubs/ovarian.htm#2

Risk Factors and Prevention

The exact cause of ovarian cancer is unknown; most cases are sporadic, occurring in women without any apparent predisposition. However, certain studies indicate that the following factors may increase or decrease the general 1.4% risk of developing the disease.

Ovulatory history. The following factors lead to a greater number of ovulations in a lifetime and moderately increase the risk of developing ovarian cancer:

  • Infertility
  • Few or no full-term pregnancies
  • First full-term pregnancy after the age of 30
  • Little or no breast-feeding
  • Never used birth-control pills
  • Hormonal stimulation of ovulation (fertility drugs)
  • First menstruation at an early age and late menopause

Women who have had 3 or 4 full-term pregnancies have about half the risk of women who have had none. Breast-feeding also decreases the risk, and the longer the period of breast-feeding, the lower the risk. Birth-control pills decrease the risk by 5% to 10% per year used. Taking the pill for 5 years therefore reduces the risk by half. The protective effect seems to last at least 10 years after the interruption of oral contraception.

Age. Most ovarian cancers occur in women over the age of 50, with the highest risk in women over 60.

Personal and family history. Personal or family history of breast, ovarian, endometrial, prostate or colon cancer increases the risk of developing ovarian cancer.

The general 1.4% probability of being diagnosed with cancer increases to 7% if a first-degree relative has ovarian cancer (mother, sister or daughter) and to 50% if 2 first-degree relatives are diagnosed. In this case the cancer may appear before the age of 50.

The presence of mutations in the tumor suppressor genes BRCA-1 and BRCA-2 can increase the risk by up to 40%. However, cancers of hereditary origin are infrequent and constitute only 3 to 5% of ovarian cancers.

Removal of the ovaries. Prophylactic oophorectomy is sometimes recommended for women with a family history of ovarian cancer. While it significantly reduces the risk of ovarian cancer, ovarian-like cancer is still possible.

Tubal ligation. This surgical operation decreases the risk of developing ovarian cancer by 41%.

Hysterectomy. Removal of the uterus may decrease the risk.

Nutrition. For every 10 g of saturated fat a woman consumes daily (about 1tablespoon), the risk of developing ovarian cancer increases by 20%, while every 10 g of vegetal fiber consumed daily decrease the risk by 37%.

Exposure to talc or asbestos. Industrial contamination, condoms dusted with talc, use of talc-based powders in the genital area, may slightly increase the probability of developing ovarian cancer. Cornstarch-based powders are a safe alternative.

North American or North European heritage and/or Ashkenazi Jewish population. Increased risk.

Living in an industrialized country. Increased risk.

Sources:

Ovarian Cancer. BC Cancer Agency. Canada. http://www.bccancer.bc.ca/cid/12.shtml#382

Ovarian Cancer Facts. National Ovarian Cancer Association. Canada http://www.ovariancanada.org

Ovarian Cancer in Canada - October 1999. Current events on cancer. Health Canada. http://www.hc-sc.gc.ca/hpb/lcdc/bc/updates/ovar_e.html

Ovarian Cancer. Microsoft Encarta Encyclopedia 2000. Microsoft Corporation, 1999. http://www.encarta.msn.com

Risk Reduction. Ovarian Cancer National Alliance. U.S.A. http://www.ovariancancer.org

What You Need To Know About... Ovarian Cancer. National Cancer Institute. U.S.A. NIH publication No. 00-1561 U.S.A. http://www.cancernet.nci.nih.gov/wyntk_pubs/ovarian.htm#2

Progression of the Disease


  1. The Ovaries
  2. The ovaries are almond-shaped glands located in the pelvis on each side of the uterus. Each ovary contains more than 100 000 ova, one of which is released each month at the moment of ovulation. Fertilization of the ova by the sperm during intercourse leads to pregnancy. At each ovulation, the ovarian follicle, a fluid-filled sack containing the ova, breaks to release the ova. The monthly cycle of rupture and healing, which results at the surface of the ovary may be one of the causes of ovarian cancer.

    The ovaries also secrete estrogens and progesterone, female sex hormones that influence the development of a woman's breasts, body shape and body hair, and that regulate the menstrual cycle and pregnancy.

  3. Types of Cancers Associated with the Ovary

    Three types of cancers can develop in the ovary:

    Epithelial cancers. They arise from the surface of the ovary are the most frequent and most lethal cancers. Ovarian cancer is a cancer of this type.

    Germ-cell cancers. They arise from the ova and are very rare.

    Stromal tumors. They arise from the supportive tissues and are also very rare.

    It should be noted that 80% of tumors of the ovary are benign (i.e. that the abnormal cells do not propagate to other tissues). This means that the presence of a tumor implies a cancer in only 20% of all cases.

  4. Stages of the Disease

    Clinicians stage the cancer according to its degree of confinement to the ovary or the extent of its spreading in the body.

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

    Stage II. The cancer has started to spread to the uterus or the fallopian tubes.

    Stage III. The cancer has spread outside the pelvis and secondary tumors have begun to develop on the surface of various organs in the abdominal cavity.

    Stage IV. Metastases have formed outside the abdominal cavity, for example in the chest cavity.

  5. Grades of the Disease

    The disease is also classified in terms of behavior of the cancerous cells (degree of organization or differentiation and speed of growth):

    Grade 1. The cells are differentiated and usually do not spread.

    Grade 2. The cells are moderately differentiated. They can detach from the tumor and spread to the pelvis and abdomen.

    Grade 3. The cells are undifferentiated. They are aggressive and tend to propagate quickly.

Sources:

A Guide to Ovarian Cancer and its Treatment. Ovarian Cancer Alliance Canada. http://www.ocac.ca

Ovarian Cancer. BC Cancer Agency. Canada. http://www.bccancer.bc.ca/cid/12.shtml#382

What You Need To Know About... Ovarian Cancer. National Cancer Institute. U.S.A. NIH publication No. 00-1561 U.S.A. http://www.cancernet.nci.nih.gov/wyntk_pubs/ovarian.htm#2

Detecting and Diagnosing Ovarian Cancer

Pelvic exam. Includes palpating the uterus, vagina, ovaries, fallopian tubes, bladder and rectum to find any abnormality in size or shape.

Transvaginal ultrasound. An image is created using high frequency sound waves aimed at the ovaries with an apparatus placed in the vagina. There is a difference between the images produced from the echo patterns of tumors and healthy tissues.

Transvaginal color flow doppler. Blood flow in the body is reproduced in computerized images with color variations. The color pattern differs according to whether blood flows through healthy or cancerous tissue.

CA-125 assay. This blood test measures the level of CA-125, a glycoprotein that is often found in greater quantities in the blood of women with ovarian cancer.

X-rays. The emission of x-rays through the body produces a two-dimensional image of the internal structures of the body, highlighting abnormalities.

Computerized axial tomography (CAT scan). The emission of x-rays following a circle arc produces a very detailed transverse image of a section of the body.

Biopsy. A tissue sample is removed for examination under a microscope. To reach the ovary, this procedure requires surgical incision of the abdominal wall.

Analysis of abdominal fluid samples. A sample of abdominal fluid taken at the time of a biopsy can provide information about the nature of the cells circulating there.

Laparotomy. The abdomen is opened surgically for diagnosis, establishing the stage of the disease, removing unhealthy tissue or taking tissue or fluid samples.

Sources:

About Ovarian Cancer. Ovarian Cancer Alliance Canada. http://www.ocac.ca

Ovarian Cancer. BC Cancer Agency. Canada. http://www.bccancer.bc.ca/cid/12.shtml#382

Diagnosis. Ovarian Cancer National Alliance. U.S.A. http://www.ovariancancer.org

What You Need To Know About... Ovarian Cancer. National Cancer Institute. U.S.A. NIH publication No. 00-1561 U.S.A. http://www.cancernet.nci.nih.gov/wyntk_pubs/ovarian.htm#2

What Every Woman Should Know About Ovarian Cancer. National Ovarian Cancer Coalition. U.S.A. http://www.ovarian.org

Women and Ovarian Cancer. Current Oncology. Vol. 5, Supl. 2, Nov. 1998. http://www.multi-med.com/oncology

 Treatment of Ovarian Cancer


  1. Conventional Therapies

Surgery. This treatment is essential to remove all visible tumor. The surgeon must be careful no to break or burst the tumor or tumors. Indeed, malignant cells escaping back into the abdomen can cause the reappearance of cancer. For this reason, other treatments must be added to the surgery, even if only one tumor is visible.

Short-term side effects of surgery include pain, discomfort, and tenderness in the area of the operation, as well as difficulty with urination and bowel movements. Removal of the ovaries causes the onset of menopause (hot flashes, vaginal dryness, permanent termination of menstrual periods, etc.) and infertility.

Chemotherapy. Chemotherapy uses drugs to kill cancer cells. The drugs are administered in the form of pills or by injection and reach their targets via the bloodstream. The chemical derivatives of platinum, carboplatin and cisplatin, as well as taxol (paclitaxel) and topotecan are common agents in the treatment of ovarian cancer.

The drugs also affect normal cells and cause a variety of side effects. Nausea, vomiting, diarrhea, fatigue, body aches, anemia, increased chance of bacterial infection, easily bleeding, numbness and tingling in hands or feet, headaches, darkening of the skin and fingernails, inflammation of the oral mucous membrane, kidney damage, some hearing loss, hair loss and loss of appetite are the main side effects associated with this approach.

Radiotherapy. Radiotherapy uses high-energy radiation from x-rays, neutrons, and other sources to kill cancer cells. The rays damage DNA, a molecule that is repaired more easily by normal cells than by cancer cells. Radiation can reach places inaccessible to surgery and causes less damage because it can be administered very precisely.

Radiotherapy is not frequently used for the treatment of ovarian cancer. It can cause fatigue, loss of appetite, nausea, vomiting, urinary discomfort, diarrhea, skin changes on the surface of the abdomen, abdominal pain and intestinal blockage.

Sources:

A Guide to Ovarian Cancer and its Treatment. Ovarian Cancer Alliance Canada. http://www.ocac.ca

Ovarian Cancer. BC Cancer Agency. Canada. http://www.bccancer.bc.ca/cid/12.shtml#382

What You Need To Know About... Ovarian Cancer. National Cancer Institute. U.S.A. NIH publication No. 00-1561 U.S.A. http://www.cancernet.nci.nih.gov/wyntk_pubs/ovarian.htm#2

Women and Ovarian Cancer. Current Oncology. Vol. 5, Supl. 2, Nov. 1998. http://www.multi-med.com/oncology

  1. Main Experimental Approaches

    Immunotherapy. Immunological approaches aim at increasing the effectiveness of the patient's immune system by increasing the number of lymphocytes or antibodies directed against a tumor or by making cancer cells more easily recognizable to the immune system.

    Anti-angiogenesis. Anti-angiogenesis aims at blocking the formation of new blood vessels in the tumor to prevent the cancer cells from being nourished. The tumor regresses due to a lack of the nutrients necessary for its growth.

    Senescence. Molecules that act on the aging of the cells could be effective for the treatment of cancers by triggering cell death. These molecules inform the cells when an internal element necessary for their function is defective. This event triggers the death of the cell through a mechanism similar to that involved in leaves falling in autumn.

    Gene therapy. Gene therapy uses DNA. With this approach, a therapeutic gene is integrated with the lymphocytes of the patient, the cancerous cells, or with other accessory cells that will be used for the treatment.

    Sources:

    Ovarian Cancer Research Notebook. National Ovarian Cancer Association. Canada. http://www.slip.net/~mcdavis/ovarian.html



Author: Liz Wirtanen, Ph.D.


© 2001 Iriscience inc. All rights reserved.

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