Ovarian Cancer Statistics

• In the UK, ovarian cancer is diagnosed in around 7,400 women each year.
• Ovarian cancer has the highest mortality rate of all the gynaecological cancers.
• Despite significant efforts to develop new drugs and treatment strategies, ovarian cancer survival rates have remained much poorer than other cancers. The 5-year survival rate for ovarian cancer is around 45%.

Genetic Alterations and Cancer Risk

15-20% (up to 1 in 5) of ovarian cancers are caused by gene alterations which run in families. Alterations in the BRCA1, BRCA2, RAD51C, RAD51D, BRIP1, and PALB2 genes are associated with an increased risk of ovarian cancer.

Risk is often described as a percentage. If an individual’s risk is 10%, this means that 1 in 10 people who carry this gene will develop this cancer during their lifetime (up to age 80 years).

The BRCA1 and BRCA2 genes are the most common genes associated with ovarian cancer. Individuals who carry a BRCA1 gene alteration have a 44% lifetime risk of developing ovarian cancer. For individuals with a BRCA2 gene alteration, the lifetime risk is 17%. BRCA1 and BRCA2 gene alterations are also associated with a 69-72% risk of breast cancer. This is much higher than the risk for individuals who do not carry a gene alteration. In the general population, 1 in 50 (2%) women get ovarian cancer and 1 in 8 (12%) get breast cancer over their lifetime.

More recently, other genes including RAD51C, RAD51D, BRIP1, and PALB2, have also been found to be associated with ovarian cancer. The lifetime risk of developing ovarian cancer with these gene alterations is between 5-13%. Table 1 below summarises these risks.

Screening and Prevention

There is currently no screening programme for ovarian cancer available on the National Health Service (NHS) as ovarian cancer screening has not yet been shown to save lives.

The most effective method to prevent ovarian cancer is surgery to remove both the fallopian tubes (‘tubes’) and ovaries. This procedure is called ‘risk reducing salpingo-oophorectomy’ (RRSO). This significantly reduces the risk of ovarian cancer by up to 96% and is offered to individuals at increased risk once they have completed their family. After RRSO, there remains a very small residual risk of primary peritoneal cancer (cancer of the lining of the abdomen; similar to ovarian cancer).

In premenopausal women, removing the ovaries causes early menopause, which causes symptoms and may have long-term consequences for general health. Early menopause results in symptoms such as hot flushes, changes in mood, irritability and impaired sexual function. It also increases the risk of osteoporosis (brittle bones), heart disease, deaths from heart disease, stroke and dementia. These risks can be reduced by taking hormone replacement therapy (HRT). However, some individuals may not be able to take HRT because of certain health problems.

Rationale for A Two-Step Procedure ‘RRESDO’

Current research suggests that a significant number (50-70%) of cancers of the ovary actually start in the tubes. This has led to the proposal of an alternative strategy for reducing ovarian cancer risk, in which women are offered preventive surgery in two steps. This procedure is called ‘risk reducing early salpingectomy with delayed oophorectomy’ (RRESDO).

The first step involves an operation to remove the tubes only (early salpingectomy). The second step involves removing the ovaries (delayed oophorectomy) in a second operation.  This can take place at any time after the first operation, at a time up to the individual’s choosing. Alternatively, individuals can have the second operation once they have reached menopause naturally (which on average is 51 years in the UK).

RRESDO will offer a degree of protection against ovarian cancer in pre-menopausal women whilst avoiding the long-term health consequences of early menopause.

However, the overall impact of this novel two-step prevention strategy has not yet been adequately studied. We do not know for sure how much protection the first operation (to remove the tubes only) provides, compared to having both the tubes and ovaries removed. The impact of RRESDO on sexual function, menopause and quality of life is unknown. Careful evaluation of the impact of this new approach is essential before this can be rolled out within the NHS.