Between 2002 and 2012 ovarian cancer deaths fell and are predicted to continue to decline in the USA, European Union and in Japan, in a smaller degree, by 2020. This prediction is according to new research published in the leading cancer journal Annals of Oncology. The use of oral contraceptives and the long-term protection against ovarian cancer that they provide may be the main reason for the decline. Professor Carlo La Vecchia (MD) from the Faculty of Medicine, University of Milan, Italy says the decline in hormone replacement therapy to manage menopausal symptoms and better diagnosis and treatment may also play a role.
The data on deaths from ovarian cancer from 1970 to the most recent available year from the World Health Organization shows researchers that in the 28 countries of the EU, death rates decreased by 10% between 2002 and 2012 from an age standardized death rate per 100,000 women of 5.76 to 5.19.
Decline in the USA was even greater with a 16% drop in death rates from 5.76 per 100,000 in 2002 to 4.85 in 2012. The ovarian cancer death rates in Canada, over the same period, also dropped by nearly 8%, and Japan had a lower rate of ovarian cancer deaths than many other countries. Their death rate fell by 2% from 3.3 to 3.28 per 100,000. Australia rate declined by nearly 12% from 4.84 to 4.27 and New Zealand dropped by 12% from 5.61 to 4.93 per 100,000 women.
The pattern of decreases was inconsistent in some parts of the world as in Latin American countries and in Europe. The percentage decrease ranged from 0.6% in Hungary to over 28% in Estonia, in the European countries. Bulgaria was the only country to show an increase. The UK had a 22% decrease in death rates. Austria decreased their rate by 18%, Denmark by 24% and Sweden by 24%. Argentina, Chile and Uruguay showed decreases, but Brazil, Colombia, Cuba, Mexico and Venezuela all showed increases in death rates.
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 most likely because of more uniform use of oral contraceptives across the continent, as well as reproductive factors, such as how many children a woman has.
The mixed patterns in Europe help to explain the difference in the size of the decrease in ovarian cancer deaths between the EU and the USA, because American women also started to use oral contraceptive earlier. Japan now has higher rates that were traditionally low in the young, than the USA or the EU, indicating infrequent oral contraceptive use. Researchers have predicted the age-standardized ovarian cancer death rates for France, Germany, Italy, Poland, Spain, the USA and the EU and Japan, up to 2020. It is expected there will be a 15% decline in the USA and a 10% decline in the EU and Japan. Spain showed a slight increase from 3.7 per 100,000 women to 3.9. This might be due to the fact that those that are middle-aged women or are now elderly, were less likely to use oral contraceptives when they were young.
It was commented that the findings of Professor La Vecchia and his colleagues are important as they show how past use of hormone treatments has an impact on the mortality from ovarian cancer at the population level. Early detection strategies are being developed and as novel options become available, we enhance our ability to reduce ovarian cancer mortality.
-Dr Fredda Branyon