Minnesota Oncology

Ovarian Cancer

Overview

Ovarian cancer is a common malignancy in women in the United States, with about 21,650 new cases diagnosed each year.[1] The ovaries are small female reproductive organs that reside in the pelvis. The ovary makes female hormones and stores all of the egg cells, which are released once a month during ovulation. There are two ovaries, one on each side of the uterus, or womb. Egg cells are delivered from the ovaries to the uterus by hollow organs called fallopian tubes.

Some ovarian tumors are benign (not cancerous). Malignant (cancerous) ovarian tumors can originate from the surface epithelium (cells covering or lining the ovaries), germ cells (cells that are destined to form eggs), or sex cord-stromal cells (cells that secrete hormones and connect the different structures of the ovaries). The majority of ovarian cancers develop from cells in the lining of the ovary. These are referred to collectively as epithelial ovarian cancers. In this treatment overview, the term ovarian cancer refers to epithelial ovarian cancer. Benign ovarian tumors and ovarian germ cell tumors are not further discussed in this section.

Common Epithelial Tumors: Common epithelial cancers that start in the surface epithelium account for the majority of ovarian cancers and include the following types:

  • Serous: This is the most common type of ovarian cancer and accounts for about 40% of common epithelial cancers. It occurs most often in women between the ages of 40 and 60.
  • Endometrioid: This type of ovarian cancer accounts for about 20% of common epithelial cancers and is associated with endometriosis in 5% and endometrial carcinoma (cancer of the womb) in 20% of cases. It occurs most often in women between the ages of 50 and 70.
  • Mucinous: Mucinous cancers account for 6-10% of common epithelial ovarian cancer and most often affect women between 30 to 50 years of age.
  • Clear Cell Carcinoma: Clear cell carcinomas account for about 5% of common epithelial tumors and most often affect women between age 40 and 80.
  • Undifferentiated Cancers: The remaining 15% of common epithelial cancers are referred to as undifferentiated tumors because their exact cell of origin cannot be determined under a microscope.
  • Borderline Ovarian Tumors: These ovarian tumors of low malignant potential are a subgroup of common epithelial tumors that occur in 10-15% of cases. These tumors are between cancerous and non-cancerous in nature. They originate on the surface of the ovary, but do not invade deeper tissues of the ovary. They have a better prognosis (prediction about the possible outcome of a disease) and cure rate than invasive ovarian tumors.

Because epithelial ovarian cancers begin deep in the pelvis, they often do not cause any symptoms until they are at an advanced stage. Furthermore, many of the symptoms of ovarian cancer are hard to differentiate from symptoms experienced by women who do not have ovarian cancer, such as back pain, fatigue, abdominal bloating, constipation, vague abdominal pain, and urinary symptoms.  Because of the lack of specificity of early ovarian cancer symptoms,[2] the majority of women (roughly 70%) already have advanced cancer at the time of diagnosis.[3] Ovarian cancer is often originally suspected in women when their physician finds an abnormal pelvic growth during an internal pelvic examination. Ovarian cancer may spread to the lining of the abdominal cavity and lead to the buildup of fluid inside the abdomen, called ascites. Ovarian cancer may cause symptoms such as swelling of the abdomen, pain, irregular bowel movements or difficulty breathing when fluid places pressure on the lungs.

The optimal treatment of ovarian cancer requires a combination of surgery, chemotherapy and, in some rare cases, radiation therapy. When ovarian cancer is suspected because of pelvic growth, additional evaluation is necessary. Ovarian cancers may spread to other organs in the pelvis, local or regional lymph nodes, the surface of the abdominal contents, or through the blood to other locations in the body, most frequently to the bowel, bladder, uterus, lungs, and liver.[4] In order to effectively plan treatment, it is important to first determine the extent of the spread or the stage of the cancer. In order to gain the most information prior to surgery, a number of tests are performed. These may include an ultrasound of the abdomen and pelvis and several blood tests, including a CA-125 level.

Elevated levels of the protein CA-125 in the blood have been associated with ovarian cancer. However, the presence of elevated levels of CA-125 in the blood does not always indicate the presence of ovarian cancer because CA-125 levels can be elevated in a number of other conditions. The normal level of CA-125 is less than 35 units per milliliter in the blood. In general, the higher the level of CA-125 found, the greater the chance of having ovarian cancer, especially for women past menopause. Once a diagnosis of ovarian cancer has been established, the level of CA-125 in the blood is a useful indicator of cancer growth during or after treatment.

Accurate surgical evaluation of ovarian cancer is necessary for nearly all patients and can only be accomplished during a laparotomy to determine the stage of the cancer and to remove as much cancer as possible. Patients who have already undergone surgery for ovarian cancer and know their stage of cancer may select from the options below. Patients who have not yet undergone surgery can select Surgical Management of Ovarian Cancer.

Following surgical removal and staging of ovarian cancer, a final stage will be given. A Roman numeral from I to IV describes the stage and a letter from “A” to “C” describes a sub-stage. All new treatment information concerning ovarian cancer is categorized and discussed by the stage. In order to learn more about the most recent information available concerning the treatment of ovarian cancer, click on the stage for which you are interested.

Stage I: Cancer is found only in one or both of the ovaries. Cancer cells may also be found in abdominal fluid, or ascites.

Stage II: Cancer is found in the ovaries and has spread to the uterus (womb), the fallopian tubes, or other areas within the pelvis. Cancer cells may also be found in abdominal fluid, or ascites.

Stage III: Cancer is found in the ovaries and has spread to other body locations within the abdomen, such as the surface of the liver, intestine or lymph nodes.

Stage IV: Cancer is found in the ovaries and has spread outside the abdomen  or inside of the liver.

Recurrent or Refractory: Recurrent disease means that the cancer has returned (recurred) after it has been treated. Refractory disease means the cancer is no longer responding to treatment.

References:

[1] American Cancer Society. Cancer Facts & Figures 2008. Available at: http://www.cancer.org/docroot/STT/stt_0.asp (Accessed September 29, 2008).

[2] Chobanian N, Dietrich CS. Ovarian Cancer. Surgical Clinics of North America. 2008; 88:285-99, vi.

[3] Ries LAG, Melbert D, Krapcho M, Stinchcomb DG, Howlader N, Horner MJ, Mariotto A, Miller BA, Feuer EJ, Altekruse SF, Lewis DR, Clegg L, Eisner MP, Reichman M, Edwards BK (eds). SEER Cancer Statistics Review, 1975-2005, National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/csr/1975_2005/, based on November 2007 SEER data submission, posted to the SEER web site, 2008.

[4] Armstrong, D. Ovaries and fallopian tubes. In: Abeloff MD ed. Abeloff’s Clinical Oncology, 4th ed. Philadelphia: Churchill Livingstone, 2008: 1827-50.

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