In Japan, the ovarian cancer death rate fell by 2 percent from 3.3 to 3.28 per 100,000.
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“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”, said lead researcher Carlo La Vecchia, Professor at University of Milan in Italy.
Large decreases occurred in Australia and New Zealand between 2002 and 2011.
“The main reason for the favourable trends is the use of oral contraceptives, particularly, in the United States and countries of the European Union where oral contraceptives were introduced earlier”, they said.
HRT, which uses oestrogen or progestogen to ease menopausal symptoms such as hot flushes, vaginal dryness and a low sex drive, is thought to increase the risk of ovarian cancer – by as much as 40 percent according to a 2015 study.
However, in some parts of the world the pattern of declining death rates was inconsistent – for example, in Latin American countries and in Europe.
“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 son this may also help to explain the fall in death rates among middle-aged and older women in these countries”.
In Britain, there was a 22 per cent decrease in death rates, which fell from 7.5 to 5.9 per 100,000 women. In Canada ovarian cancer death rates decreased over the same period by almost 8% from 5.42 to 4.95.
In Canada ovarian cancer death rates decreased by almost 8 percent from 5.42 to 4.95 per 100,000 women over the same period.
In Latin America, deaths decreased in Argentina, Chile and Uruguay, but rose in Brazil, Colombia, Cuba, Mexico and Venezuela.
The researchers said falling use of HRT to cope with the menopause, increasing use of the Pill, and a better detection rate and treatments had all combined to drive down cancer deaths. In each instance, the decline in ovarian cancer rates was strongly correlated to oral contraceptive use.
The researchers referred to a 2008 Lancet review, which estimated that using oral contraceptives for 10 years would reduce ovarian cancer incidence before age 75 from 1.2 to 0.8 per 100 users and mortality from 0.7 to 0.5 per 100.
But while the drugs can transform the lives of many women, they also raise the risk of cancer – meaning that a small number will develop the disease who would otherwise not have.
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Some of the countries where long-term use of HRT used to be high and has now declined – with women now opting to take it for just a couple of years or not at all – such as the UK, USA and Germany, are also countries that have seen marked drops in death rates.
