Ovarian cancer at a glance
- Ovarian cancer is the uncontrolled growth of malignant cells originating from one or both of a woman’s ovaries.
- This type of cancer usually only causes minor symptoms early on, and is therefore frequently diagnosed in a later stage, making it more difficult to treat.
- Common risk factors for ovarian cancer include age (it most commonly affects post-menopausal women), family history, genetic predisposition and obesity.
- Ovarian cancer is usually treated with a combination of surgery and chemotherapy.
What is ovarian cancer?
Ovarian cancer is the uncontrolled growth of cells originating from the ovaries. The ovaries are a pair of female reproductive glands located in a woman’s pelvic region on each side of her uterus. They are responsible for producing eggs called ova as well as estrogen and progesterone, two important female sex hormones.
Cancer is uncontrolled cell growth that often leads to the formation of malignant (cancerous) tumors, in this case on the ovaries. These tumors can spread beyond the ovaries to other parts of the body as the cancer progresses.
Noncancerous growths called ovarian cysts are far more common than ovarian cancer. While ovarian cysts may cause complications including pain and infertility, they do not spread beyond the ovaries to invade other parts of the body.
According to the American Cancer Society, ovarian cancer ranks fifth among cancer deaths in women, and approximately 1 in 75 women will develop it in their lifetime. Ovarian cancer is responsible for more deaths than any other female reproductive cancer due to the fact that it is often not caught until it has progressed to an advanced stage.
Types of ovarian cancer
Ovarian cancer is classified based on what type of cell the cancer originates from. The ovaries are comprised of primarily three types of cells that correspond to the three main types of ovarian cancer:
- Epithelial ovarian cancer originates from epithelial cells. These types of cells comprise the outer lining of the ovaries. This is the most common type of ovarian cancer, accounting for 85 to 90 percent of cases.
- Germ cell ovarian cancer originates from the egg cells within the ovaries. This type tends to affect teenagers and young women. While far less common, this type is usually very treatable and has a high survival rate.
- Stromal ovarian cancer is a rare subtype originating from the connective tissue on the ovaries. This type tends to affect the body’s hormones. Because of this, it is often detected at an early stage and has a good prognosis compared with epithelial cancers.
Stages of ovarian cancer
Ovarian cancer is classified by stages, which correspond to how far the cancer has spread. Like many cancers, ovarian cancer is far more treatable when it is caught in the early stages.
- Stage I – the cancer is on one or both ovaries, but has not spread beyond them.
- Stage II – the cancer is on one or both ovaries and has spread to other pelvic organs such as the uterus.
- Stage III – growth has spread beyond the ovaries and pelvic region and may be found in the lymph nodes.
- Stage IV – widespread cancer growth, including tumors inside the liver, spleen, lungs, bones and other organs.
Symptoms and signs of ovarian cancer
In the early stages of ovarian cancer, there are often few or no symptoms. Early symptoms mimic more common disorders such as premenstrual syndrome (PMS), indigestion and chronic fatigue syndrome. The most common symptoms of early stage ovarian cancer include:
- Pelvic pain or pressure
- Abdominal bloating
- Reduced appetite
- Bowel movement changes
- Frequent urination
- Low energy or tiring easily.
When the above symptoms persist over multiple weeks, a woman should see her doctor for an evaluation. When these symptoms are caused by cancer, they get worse over time and do not respond to conventional treatment methods such as rest, diet changes and exercise. More serious symptoms and complications do not usually arise until ovarian cancer reaches the later stages when it is much more difficult to treat.
Causes and risk factors
The following are known risk factors for developing ovarian cancer.
The majority of ovarian cancers affect women who have gone through menopause. Half of all diagnoses are made in women over the age of 63.
Family history and genetics
Family history is a significant risk factor for developing ovarian cancer, particularly if an immediate family member such as a sister or mother had the disease.
Genetic mutations inherited from one or both parents are sometimes responsible for the development of ovarian cancer. This includes defects in the BRCA1 and BRCA2 genes, which also cause other types of cancer. Women with these specific gene mutations are at a substantially higher risk of developing ovarian cancer.
BRCA1 and BRCA2 gene mutations are relatively rare, accounting for about 12 percent of ovarian cancer cases. But testing that detects the mutation is available and may be recommended for women who have a family history of certain cancer types (including ovarian cancer).
The risk for ovarian cancer increases along with the total number of times a woman has ovulated throughout her lifetime. Therefore, a woman may be at greater risk if she:
- Began menstruating at an early age
- Never had children
- Never took birth control
- Entered menopause after age 50.
Infertility is defined as the inability to get pregnant despite having frequent unprotected sex for a year or more. It is a known ovarian cancer risk factor.
Women with a body mass index (BMI) of 30 or higher are at a greater risk of developing ovarian cancer.
Ovarian cancer treatment
Most commonly, ovarian cancer is treated using surgery and chemotherapy or a combination of the two. Some patients with ovarian cancer may be candidates for clinical trials, which involve new drugs and treatment methods not available to the general public.
Clinical trials use experimental, cutting-edge medications to treat cancer.
Surgery is the most common treatment method for ovarian cancer, and it is used for two purposes. First, surgery gives the doctor an opportunity to assess how far the cancer has spread (this is called staging). Next, surgery allows the doctor to physically remove as much of the cancer as possible (this is called debulking).
Ovarian cancer surgery usually involves the removal of the ovaries (oophorectormy) and uterus (hysterectomy), depending on how far the tumors have spread.
Chemotherapy uses special anti-cancer drugs to stop cells from dividing and slow the spread of cancer. It may be administered orally or intravenously.
In most cases of ovarian cancer, chemotherapy will be administered after surgical staging and debulking. Chemotherapy seeks to stop whatever cancer could not be removed via surgery by attacking the cancer cells on a cellular level.