Learn about the subtypes of ovarian cancer and key facts about this disease.

Statistics

What is ovarian cancer?
Ovarian cancer is a growth of abnormal malignant cells that begins in the ovaries
(women’s reproductive glands that produce ova). Cancer that spreads to the ovaries
but originates at another site is not considered ovarian cancer.

Ovarian tumors can be benign (noncancerous) or malignant (cancerous).
Although abnormal, cells of benign tumors do not metastasize (spread to other parts of the body).
Malignant cancer cells in the ovaries can metastasize in two ways:

  • directly to other organs in the pelvis and abdomen (the more common way)
  • through the bloodstream or lymph nodes to other parts of the body

While the causes of ovarian cancer are unknown, some theories exist.

  • genetic errors may occur because of the repeated “wear and tear” of the monthly release of an egg.
  • increased hormone levels before and during ovulation may stimulate the growth of abnormal cells.

For more specific information about the different types of ovarian cancer, see the American Cancer Society’s detailed guide: click here.

Types of Ovarian Cancer
Different types of ovarian cancer are classified according to the type of cell from which they start.
Epithelial tumors – About 90 percent of ovarian cancers develop in the epithelium, the thin layer of tissue that covers the ovaries. This form of ovarian cancer generally occurs in postmenopausal women.
Germ cell carcinoma tumors – Making up about five percent of ovarian cancer cases, this type begins in the cells that form eggs. While germ cell carcinoma can occur in women of any age, it tends to
be found most often in women in their early 20s. Six main kinds of germ cell carcinoma exist, but the three most common types are: teratomas, dysgerminomas and endodermal sinus tumors.
Many tumors that arise in the germ cells are benign.
Stromal carcinoma tumors – Ovarian stromal carcinoma accounts for about five percent of ovarian cancer cases. It develops in the connective tissue cells that hold the ovary together and those that produce the female hormones estrogen and progesterone. The two most common types are granulosa cell tumors and sertoli-leydig cell tumors. Unlike epithelial ovarian carcinoma, 70 percent of stromal carcinoma cases are diagnosed in Stage I.
Small cell carcinoma of the ovary – Small cell carcinoma of the ovary (SCCO) is a rare, highly malignant tumor that affects mainly young women, with a median age at diagnosis of 24 years old. The subtypes of SCCO include pulmonary, neuro-endocrine and hypercalcemic. SCCO accounts for 0.1 percent of ovarian cancer cases. Approximately two-thirds of patients with SCCO have hypercalcemia. The symptoms are the same as other types of ovarian cancer.

For more specific information about the different types of ovarian cancer, see the American Cancer Society’s detailed guide: click here.

Stages of Ovarian Cancer

The stages of ovarian cancer are determined by how far the cancer has spread.The stage of ovarian cancer at diagnosis is the most important indicator of prognosis.

SEER Cancer Statistics Factsheets: Ovary Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/ovary.html

SEER Cancer Statistics Factsheets: Ovary Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/ovary.html

Stage I – Cancer is limited to one or both ovaries.IA – Cancer is limited to one ovary and the tumor is confined to the inside of the ovary. No ascites containing malignant cells is present, and the surface of the tumor has not ruptured.IB – Cancer is limited to both ovaries without any tumors on the ovaries’ outer surfaces. No ascites containing malignant cells is present, and the surface of the tumor has not ruptured.

IC – The tumor is classified as either Stage IA or IB and one or more of the
following conditions exist:

  • a tumor on the outer surface of one or both ovaries;
  • at least one ruptured tumor;
  • ascites or abdominal (peritoneal) washings containing malignant cells.

Stage II – The tumor involves one or both ovaries and extends to other pelvic
structures.

IIA – The cancer has extended to and/or involves the uterus and/or the fallopian
tubes.

IIB – The cancer has extended to the bladder or rectum.

IIC – The tumor is classified as either Stage IIA or IIB and one or more of the
following conditions exist:

  •  a tumor on the outer surface of one or both ovaries;
  •  at least one ruptured tumor;
  •  ascites containing malignant cells or abdominal (peritoneal) washings containing malignant cells.

Stage III – The tumor involves one or both ovaries, and one or both of the
following exist:

The cancer has spread beyond the pelvis to the lining of the abdomen;

The cancer has spread to the lymph nodes. The tumor is limited to the true pelvis but with histologically-proven malignant extension to the small bowel or omentum (peritoneum fold).

IIIA – The tumor is in one or both of the ovaries. While surgeons cannot see cancer in the abdomen, and the cancer has not spread to the lymph nodes, biopsies checked under a microscope reveal tiny deposits of cancer in the abdominal (peritoneal) surfaces.

IIIB – The tumor is in one or both ovaries, and deposits of cancer are present in the abdomen that are large enough for the surgeon to see but do not exceed two cm in diameter. The cancer has not spread to the lymph nodes.

IIIC – The tumor is visible in one or both ovaries, and one or both of the following conditions exists:

  •  the cancer has spread to lymph nodes;
  •  the deposits of cancer exceed two cm in diameter and are found in the abdomen.

Stage IV- Growth of the cancer involves one or both ovaries and distant metastases to the liver or lungs have occurred. Finding ovarian cancer cells in the excess fluid accumulated around the
lungs (pleural fluid) also shows evidence of stage IV.

For more specific information about ovarian cancer, see the American Cancer Society’s Detailed Guide

Statistics
In the United States, doctors must report any diagnosis of cancer to a state registry. The federal government, through the Centers for Disease Control and Prevention’s National Program of Cancer Registries, oversees the registries in 45 states, the District of Columbia and three territories. The Surveillance, Epidemiology and End Results (SEER) Program of the National Cancer Institute funds the remaining five statewide cancer registries. Together, the two programs cover the country’s population.The following statistics come primarily from the most recent findings of the Surveillance, Epidemiology and End Results (SEER) Program of the National Cancer Institute. SEER numbers are age-adjusted and based on actual data.
SEER Cancer Statistics Factsheets: Ovary Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/ovary.html

SEER Cancer Statistics Factsheets: Ovary Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/ovary.html

SEER data is available for most data through 2010. More recent statistics, such as 2014 incidence numbers, are projections from the American Cancer Society.  The American Cancer Society estimates that in 2014, about 21,980 new cases of ovarian cancer will be diagnosed and 14,270 women will die of ovarian cancer in the United States. Mortality rates for ovarian cancer have declined only slightly in the forty years since the “War on Cancer” was declared. However, other cancers have shown a much greater reduction in mortality, due to the availability of early detection tests and improved treatments.  The Surveillance, Epidemiology and End Results (SEER) Program reports that on January 1, 2010 in the United States approximately 186,138 women were alive who had been diagnosed with ovarian cancer (including those who had been cured of the disease).
SEER Cancer Statistics Factsheets: Ovary Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/ovary.html

SEER Cancer Statistics Factsheets: Ovary Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/ovary.html

Ovarian cancer accounts for approximately three percent of cancers in women.
While the 11th most common cancer among women, ovarian cancer is the fifth leading cause of cancer-related death among women, and is the deadliest of gynecologic cancers. Mortality rates are slightly higher for Caucasian women than for African-American women.
A Woman’s Lifetime Risk:
A woman’s lifetime risk of developing invasive ovarian cancer is 1 in 72. A woman’s lifetime risk of dying from invasive ovarian cancer is 1 in 100.
Age:
Ovarian cancer rates are highest in women aged 55-64 years. The median age at which women are diagnosed is 63, meaning that half of women are younger than 63 when diagnosed with ovarian cancer and half are older.
The median age of death from ovarian cancer is 71. Ovarian cancer survival rates are much lower than other cancers that affect women. Five-year survival rates are commonly used to compare different cancers. The relative five-year survival rate for ovarian cancer is 44.2 percent. Survival rates vary greatly depending on the stage of diagnosis.  Women diagnosed at an early stage—before the cancer has spread—have a much higher five-year survival rate than those diagnosed at a later stage. Approximately 15 percent of ovarian cancer patients are diagnosed early with early stage disease.
SEER Cancer Statistics Factsheets: Ovary Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/ovary.html

SEER Cancer Statistics Factsheets: Ovary Cancer. National Cancer Institute. Bethesda, MD, http://seer.cancer.gov/statfacts/html/ovary.html

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