Ovarian Cancer Causes & Risks: What You Should Know

Many patients, partners and family members are left stunned and speechless upon receiving an ovarian cancer diagnosis.

“But I've always had regular PAP smears.”

“But I've always lived a healthy life.”

“But a month ago I ran a half-marathon.”

These are just some of the sentiments I hear when patients realise they suffer from the “silent killer,” ovarian cancer

Ovarian Cancer Blog

Ovarian cancer is the deadliest of all gynaecological malignancies and this year, it is anticipated we will diagnose 1,300 women in Australia with the disease. The government's frightening projection estimates that number will increase to more than 1,600 in 2020.

For these women less than half will survive more than five years.

Ovarian cancer does not have detectable early warning signs. Even if the cancer is tiny when detected, it can have already spread to the abdomen, liver and the chest. While early detection methods such as ultrasound or blood tests have been tried, no progress has been made and the technology available is not sensitive or specific enough.

Hence, screening and identification of patients with “early” disease is not possible.

Some, but not all women report symptoms such as bloating, urinary frequency and abdominal discomfort. However, once a patient has developed these symptoms, the disease has already progressed. 

While there are no specific or conclusive symptoms pointing to ovarian cancer, general symptoms can include:

  • Abdominal bloating
  • Pelvic pain and discomfort
  • Urinary frequency
  • Bowel symptoms similar to irritable bowel

What are the causes and risk factors for ovarian cancer?

Medical and public health researchers have made a strenuous effort to better identify risk factors for ovarian cancer in recent years.

Genetic factors (see below for details) are the only risk factors that increase the risk of ovarian cancer to such an extent that individual patients need to be identified and referred for prevention or prophylactic surgery. In contrast, all other factors increase the ovarian cancer risk so modestly that as doctors we are unable to identify patients who should undergo drastic measures to minimise the risk of cancer developing.

While medical research does make progress, the main question - “Why did I get ovarian cancer?” - will remain unanswerable for the vast majority of ovarian cancer patients for some time to come.

Now let's explore the three major known risk factors for ovarian cancer:


Women who carry BRCA1 or BRCA2 gene mutations are at an astronomical risk (up to 80%) for both, ovarian and breast cancer. Both are tumour suppressor genes that are inherited, even through males.

Interestingly, women with Ashkenazi Jewish ethnic background are more likely to carry this mutation.

Recent Australian research has shown that one in eight ovarian cancers are BRCA-related (inherited). While it isn't government funded, it is my strong personal recommendation that all patients with high-grade, serous ovarian cancer be tested for BRCA1 and BRCA2 to allow information to be passed on to sisters, daughters and other relatives.

Lynch Syndrome is a genetic condition, which causes bowel cancer.  In females the risk of gynaecological cancers (uterine, ovarian cancer) is higher than the risk of bowel cancer. 

Typically, an aggregation of ovarian/breast cancers or uterine/bowel cancers within a family and when patients are diagnosed at a younger than expected age should trigger the search for a genetic cause.

The implications for the patient and her family of finding a genetic fault are outlined here.


The risk of developing ovarian cancer increases with age. The average risk of ovarian cancer in Australia is 1.3%, but the risk doubles as women move into their fifties, compared to younger women.

Reproductive and hormonal factors

Women diagnosed with infertility (inability to have children), endometriosis and women who developed early puberty or late menopause are at a moderately increased risk of ovarian cancer.

What does not cause ovarian cancer?

Current research indicates that ovarian cancer is not sexually transmitted or caused by sexual intercourse, and there is also no clear linkage between the use of talcum powder and ovarian cancer.

How can ovarian cancer be prevented?

Some forms of ovarian cancer may be linked with lifestyle factors such as obesity or sedentary behaviour. A healthy weight is beneficial to reduce the risk for a number of gynaecological problems.


Ovarian cancer screening is not helpful because it is not reliable. Women are often diagnosed with ovarian cancer shortly after a “normal” ovarian cancer test.

Why isn't screening reliable?

  • Ultrasound does not detect “early” stages of ovarian cancer
  • Blood tests (e.g., CA125, HE4) can be elevated even in the absence of ovarian cancer
  • No reliable tests are presently available, though massive research efforts are being made to find a test

Risk-reducing, prophylactic surgery

The most useful strategy is to surgically remove the organs in question. Surgery virtually eliminates the risk of ovarian cancer, however it comes at an obvious price and only women who have either a confirmed genetic predisposition or who are concerned about their risk should consider this invasive step.

There are various types of surgery that make sense for women at different stages in their lives.

1. Surgery to remove both ovaries and Fallopian tubes

This is a reasonable option for any women with a confirmed genetic fault, who is over the age of 35 years and who has completed her family. The side effect is that this woman will become menopausal straight away and consideration needs to be given to the possible need of Hormonal Replacement Therapy (HRT).

2. Surgery to remove the Fallopian Tubes only

Current research suggests that a considerable percentage of “ovarian” cancer does not actually arise in the ovaries but in the Fallopian Tubes. Removing the Fallopian Tubes will not render a woman menopausal but the protective effect is expected to be less than with complete removal of the ovaries.

3. Hysterectomy & Tubal Ligation

Independent of whether the ovaries or the Fallopian Tubes or both are removed, the majority of women opt for a hysterectomy at the same time. The majority of hysterectomies can be completed by laparoscopic (key hole) surgery even if the patient has had previous surgery.

Tubal ligation with clips can also result in a modest reduction in lifetime ovarian cancer risk.  If a woman opts for surgical sterilisation, I recommend removing the fallopian tubes rather than just clipping or tying them.

What about non-invasive risk-reducing strategies?

Oral contraceptive pill

The oral contraceptive pill (OCP) reduces the risk of ovarian cancer by 50% if taken for longer than 1 year. It is a reasonable option for women at normal ovarian cancer risk (1.3% lifetime risk).  In women who carry a genetic fault the risk of ovarian cancer is up to 40% and halving the risk would leave those women still at an unacceptably high risk of ovarian cancer.

Pregnancy and breastfeeding

Pregnancy and breastfeeding reduces the risk of ovarian cancer only modestly. It is important to note though that the majority of women diagnosed with ovarian cancer have given birth and were breastfeeding.

Ovarian Cancer Awareness Month

Each year in Australia, Ovarian Cancer Awareness Month is held in February to raise awareness of this silent killer, and to recognise and honour the thousands of women and their families who have been touched by the disease. 

Each year during February, the Cherish Women's Cancer Foundation hosts the annual Battle Against Ovarian Cancer, a community beach volleyball tournament raising much-needed funds and public support for life changing gynaecological cancer research. Friends, families or corporate groups are encouraged to be part of this unique Brisbane family and fun event in the name of the women we Cherish. For more information or to enter a team visit

If you are worried about your current risk of ovarian cancer, and want to gain further knowledge or insight into your genetic disposition, reproductive or hormonal factors, please do not hesitate to contact me though my website. I will be happy to discuss your situation and options moving forward.

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