Ovarian cancer occurs when cells in one or both ovaries proliferate out of control. Although women of all ages are susceptible to ovarian cancer, about 90 percent of women diagnosed with ovarian cancer are older than 40, according to the Centers for Disease Control and Prevention.
The National Cancer Institute estimates that there will be 21,880 new cases and 13,850 deaths from ovarian cancer in the United States in 2010. Based on trends observed from 2005 to 2007, one out of 72 women born today will be diagnosed with ovarian cancer at some time during their lifetime. The overall 5-year relative survival from 1999 to 2006 was 45.6 percent, according to the National Cancer Institute, with white women having a slightly better chance of survival than black women.
There are three main types of ovarian tumors. The most common type, epithelial tumors, happens to the cells on the surface of the ovary and it accounts for 80 to 90 percent of malignant ovarian tumors, according to Johns Hopkins University. It is the fifth most frequent cause of cancer death in women, with 50 percent of all cases occurring in women older than 65. Less common are germ cell ovarian tumors, which occur in the egg-producing cells of the ovary, and sex cord stromal ovarian tumors.
Furthermore, ovarian cancer is classified by four stages. At stage I, the cancer is confined to one or both ovaries. At stage II, the cancer has spread to other locations in the pelvis, such as the uterus or fallopian tubes. Stage III ovarian cancer occurs when the cancerous cells have spread to the lining of the abdomen or to the lymph nodes within the abdomen. Most cases of ovarian cancer are diagnosed at stage III, according to the Mayo Clinic. By stage IV, the cancer has’ spread to organs and tissues beyond the abdomen.
Overall, many women with ovarian cancer have no symptoms or just mild symptoms until the disease is in an advanced stage and hard to treat, according to the National Institutes of Health. For that reason, it also has the highest mortality of all cancers of the female reproductive system, according to the National Cancer Institute.
Although some ovarian cancer patients experienced symptoms such as abdominal pain, bloating, unexplained back pain and abnormal vaginal bleeding, a 2010 study in the Journal of the National Cancer Institute found that these relatively nonspecific symptoms may not definitively point toward ovarian cancer. Doctors would have to evaluate 100 women with these symptoms to come across one case of ovarian cancer. Nonetheless, a better awareness of your body’s subtle changes is not entirely pointless and it could still lead to earlier testing, detection and treatment.
Diagnosis & Tests
There is currently no standardized screening test available for reliably detecting ovarian cancer, according to the Mayo Clinic. Routine screening for ovarian cancer with serum markers, such as CA125 protein levels, transvaginal ultrasound or pelvic examinations, have not been proven to result in an earlier diagnosis or better chance at surviving the disease. A CA125 screening program of 22,000 postmenopausal women, which screens for the tumor-associated protein, detected 11 out of 19 cases of ovarian cancer, for an apparent sensitivity of 58 percent. Of that, only three out of those 11 cases are at stage I.
If the above tests do not rule out ovarian cancer, doctors would then proceed to do a laparotomy, which is a slightly less invasive surgical procedure, according to the Mayo Clinic. The surgeon may remove a tissue mass or abdominal fluid to determine whether there’s cancerous growth.
A pap test may be an effective way to screen for cervical cancer, but it does not screen for ovarian cancer.
Treatments & Medication
Standard treatments for ovarian cancer include surgery, where as much of the tumor and the affected tissues are removed. Radiation therapy and chemotherapy may also halt cancer progression by killing the cancer cells or keeping them from dividing, according to the National Cancer Institute, and could be administered before or after surgery. Novel treatments currently under investigation include new chemotherapy drugs, vaccines, gene therapy and immunotherapy, according to the Mayo Clinic.
Many cancer treatments can have adverse side effects. For example, bevacizumab (sometimes referred to by its brand name Avastin) works by disrupting the blood supply to the tumor, possibly causing it to shrink. Yet gastrointestinal perforation is significantly increased for those who take the drug, according to a 2009 review published in Lancet Oncology that studied 12,294 patients. As for chemotherapy, side effects such as abdominal pain, nausea and vomiting may prevent many women from completing a full course of treatment, according to the Mayo Clinic.
For high-risk women, such as those with a first-degree relative like a mother, daughter or sister diagnosed with the disease, they might consider aggressive preventative measures such as prophylactic oophorectomy, where both ovaries are removed in hopes to prevent the onset of ovarian cancer. However, a 2008 review of various cohort studies shows that premature loss of ovarian function before the onset of menopause could in turn increase the lifetime risk of premature death, cardiovascular disease, Parkinsonism, osteoporosis and more. Therefore, these risks should be carefully weighed before making any drastic decisions.