Deaths from ovarian cancer have been falling worldwide and are expected to continue to fall in the coming years, a new study has found.

According to the findings, the main reason for this is women's use of oral contraceptives. Oral contraceptives have been shown to reduce the risk of developing this type of cancer.

Ovarian cancer is often referred to as the ‘silent killer' because its symptoms, which can include bloating and changes in bowel habits, are often confused with other illnesses. As a result, most patients are not diagnosed until they are in the advanced stages of the disease.

A majority of patients die within five years of their diagnosis. However, if caught at its earliest stage, there is a 90% survival rate.

Italian researchers analysed data on ovarian cancer deaths from 1970 to the most recent year available, 2012. They found that between 2002 and 2012, deaths decreased in the European Union (EU) by an average of 10%.
In the US, deaths fell by 16%, while they fell by almost 8% in Canada.

The death rate in Japan fell by 2%, however the researchers noted that this country already has a lower rate of death from ovarian cancer compared to many other countries.

Meanwhile, the death rate fell by around 12% in both Australia and New Zealand.

The researchers noted inconsistent patterns in some regions. For example, in Europe, the death rate fell in Hungary by less than 1%, but in Estonia, it fell by 28%.

"The large variations in death rates between European countries have reduced since the 1990s when there was a threefold variation across Europe from 3.6 per 100,000 in Portugal to 9.3 in Denmark. This is likely to be due to more uniform use of oral contraceptives across the continent, as well as reproductive factors, such as how many children a woman has," commented Prof Carlo La Vecchia of the University of Milan.

The researchers also suggested that a decline in the use of hormone replacement therapy (HRT) to manage symptoms of the menopause may have played a role in the reduced death rates.

"Women in countries such as Germany, the UK and the US were more likely to use HRT to manage menopausal symptoms than in some other countries. The use of HRT declined after the report from the Women's Health Initiative in 2002 highlighted the increased risk of cardiovascular disease, as well as breast and ovarian cancer, and so this may also help to explain the fall in death rates among middle-aged and older women in these countries," said researcher, Dr Eva Negri, of the IRCCS Istituto di Ricerche Farmacologiche Mario Negri in Milan.

The researchers have predicted that ovarian death rates will continue to decline in the EU, the US and Japan up to 2020.

Details of these findings are published in the journal, Annals of Oncology.