Ovarian cancer refers to any cancerous growth that begins in the ovary. This is the part of the female body that produces eggs.
Ovarian cancer is now the fifth most common cause of cancer-related death among females in the United States. That said, deaths from ovarian cancer have been falling in the U.S. over the past 2 decades, according to the American Cancer Society (ACS).
The ACS estimates that in 2019, around 22,530 people may receive a diagnosis of ovarian cancer. Around 13,980 people are likely to die from this condition.
Most ovarian cancers start in the epithelium, or outer lining, of the ovary. In the early stages, there may be few or no symptoms.
If symptoms do occur, they can resemble those of other conditions, such as premenstrual syndrome, irritable bowel syndrome, or a temporary bladder problem. However, in ovarian cancer, the symptoms will persist and worsen.
Early symptoms may include:
- Pain or pressure in the pelvis
- Unexpected vaginal bleeding
- Back or abdomen
- Feeling full rapidly when eating
- Changes in urination patterns, such as more frequent urination
- Changes in bowel habits, such as constipation.
If any of these symptoms last for 2 weeks or more, a person should see a doctor.
There may also be:
The symptoms can change if cancer spreads to other parts of the body.
Causes and risk factors
Ovarian cancer develops when cells in this area of the body divide and multiply in an uncontrolled way.
Why ovarian cancer happens is not clear, but experts have identified some risk factors. They include:
Having a close relative with a history of ovarian or breast cancer increases a person’s chance of developing ovarian cancer themselves.
Undergoing genetic screening for mutations in the BRCA gene may help determine if someone has a higher risk of both ovarian and breast cancer.
Around 50% of ovarian cancer cases occur after the age of 63 years.
Having had one or more full-term pregnancies is associated with a lower risk of ovarian cancer. The more pregnancies a woman has, the lower the risk seems to be. Breastfeeding may also lower the risk.
However, having children later in life (after age 35) or never having children is associated with a higher risk.
People who use some type of fertility treatment may have a higher chance of developing borderline cells, but not all studies confirm this.
Females who use birth control pills or an injectable contraceptive hormone also appear to have a lower risk.
People with a history of breast cancer seem to have a higher chance of ovarian cancer. This may be due to changes in the BRCA gene.
For this reason, some people with breast cancer who test positive for this gene mutation may opt to have an oophorectomy, or surgery to remove the ovaries, as preventive therapy.
Undergoing hormone replacement therapy (HRT) after menopause appears to increase the risk of ovarian cancer.
The longer a person uses HRT, the higher the risk. However, the risk appears to fall after treatment stops.
Obesity and overweight
Ovarian cancer is more common in people with a body mass index (BMI) of over 30.
Having surgery to remove the uterus, called a hysterectomy, may reduce the risk of ovarian cancer by one-third.
Scientists have been finding links between the human papillomavirus (HPV) and various cancers, including tonsil cancer and cervical cancer.
In 2013, the authors of a meta-analysis reported finding a high rate of HPV among people with ovarian cancer. However, they could not confirm that HPV causes it, and they called for further research.
Other possible risk factors
Other factors that may increase the risk of some types of ovarian cancer include:
- having high levels of androgens, or male hormones
- dietary factors
- the use of talcum powder
However, researchers have not yet proven a link between these factors and ovarian cancer.
Risk for transgender people
Some studies suggest that having high levels of androgen may increase the risk of ovarian cancer. This may be a concern for transgender men who use hormone treatment in their transition.
A study from 2017 notes that having the ovaries removed may lower the risk, but the authors urge people to be aware that ovarian cancer remains a possibility.
The National LGBT Cancer Network points out that transgender people may have difficulty seeking regular medical help due to concerns about revealing their gender identity.
They encourage people to ask their friends, their local hospital, and their insurance company to find a suitable doctor who can help them take care of their health and their body.
If a healthcare professional diagnoses ovarian cancer, they will need to determine the stage and grade to decide on a treatment plan.
The term “stage” refers to how far cancer has spread. For example,
- Localized: Cancer cells affect only the ovaries or fallopian tubes and have not spread elsewhere.
- Regional: Cancer has spread to nearby organs, such as the uterus.
- Distant: Cancer is present elsewhere in the body. It now affects other organs, such as the lungs or liver.
The grade, meanwhile, refers to how abnormal the cancer cells appear.
Getting an early diagnosis usually means that treatment can be more effective. However, other factors can affect this.
These factors include the person’s age and overall health and the type or grade of the cancer cell, as some types are more aggressive than others.
There are over 30 types of ovarian cancer depending on the type of cell in which it starts.
There are three common cell types:
- epithelial cells, which occur in the lining of the surface of the ovary
- germ cells, which will become eggs for reproduction
- stromal cells, which release hormones and link up the structures of the ovaries
Epithelial tumors are the most common and the most invasive. They occur in around 85–90% of people with ovarian cancer.
Germ cell tumors are often benign. In 90% of cases that become cancerous, treatment is effective.
If a routine screening or symptoms suggest that a person may have ovarian cancer, a doctor will typically:
- ask the person about their personal and family medical history
- carry out a pelvic examination
They may also recommend:
Blood tests: These tests will check for high levels of a marker called CA-125.
Laparoscopy: A healthcare professional will insert a thin tube with a camera attached through a small hole in the abdomen, to see the ovaries and perhaps take a tissue sample for a biopsy.
Biopsy: This involves the microscopic examination of a tissue sample.
Only a biopsy can confirm that a person has cancer. A healthcare professional may do this as part of the initial assessment or following surgery to remove a tumor.
Treatment will depend on many factors, including:
- the type, stage, and grade of the cancer
- the individual’s age and overall health
- their personal preferences
- accessibility and affordability of treatment
Options tend to include
Surgery: The choice will depend on the type of cancer and how far it has spread. Surgical options include a hysterectomy, removing one or both ovaries, and removing affected lymph nodes. A doctor will discuss suitable options with the individual.
Chemotherapy: These drugs aim to kill cancer cells. If a person takes chemotherapy drugs by mouth, or as an injection or infusion, they will affect the whole body. Another option is intraperitoneal chemotherapy. In this case, a tube delivers the drug directly to the body area affected by cancer. Chemotherapy can have widespread adverse effects, especially if it affects the whole body.
Targeted therapy: Some treatments target specific cells that help promote cancer growth. Examples include monoclonal antibody therapy and angiogenesis inhibitors. Targeted therapy aims to limit the adverse effects by targeting specific functions.
Radiation therapy: This technique uses X-rays to kill cancer cells. One way to do this is by introducing a radioactive liquid into the peritoneum. This may help people with advanced ovarian cancer.
Immunotherapy (biotherapy): This aims to boost the immune system’s ability to defend the body against cancer. Vaccine therapy involves injecting substances that will find and kill a tumor. It may help people with advanced ovarian cancer.
Some of these are relatively new types of treatment. Some people may opt to join a clinical trial, which can give access to some of the newest approaches.
All types of ovarian cancer are treatable if a person receives a diagnosis in the early stages. Some types are also highly treatable in the later stages.
When considering survival statistics for ovarian cancer, it is also worth noting that medical advances have been improving the outlook over the past 20 years.
Nevertheless, attending the regular screening and seeking help if any symptoms appear can often lead to an early diagnosis, and this will increase the chance of receiving effective treatment.