Contraceptive use drives down ovarian cancer

The Contraceptive Pill Use is Driving down Ovarian Cancer Death Rates Worldwide

 Widespread use of oral contraceptives (OCs), particularly in the United States and certain countries in the European Union (EU), where they were introduced earlier than elsewhere, is fuelling the continued decline in death rates from ovarian cancer in many countries, a new study reveals, although mortality patterns still markedly differ in disparate parts of the world.

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"The present global report shows the persistence of falls in ovarian cancer mortality over the last decade in Europe and North America," write the researchers. "The recent favourable trends in ovarian cancer mortality in North America and Europe can be partly or largely attributed to the long-term protection of OC on ovarian cancer risk [as well as] recent declines in menopausal hormonal therapy use," they add.

Findings highlight 

 
"past use of hormone treatments has an impact on the mortality from ovarian cancer at the population level,..." commented Paolo Boffetta,

Research methodology

The research was conducted by obtaining official death records for ovarian cancer from 1970 to 2012 (or the most recent year available) from the World Health Organization (WHO) database.
Data were analyzed for 28 countries in the EU, plus 4 other European countries, 11 countries in the Americas, and 6 other countries worldwide.

Results

"At all ages, EU mortality rates decreased from 5.8 to 5.2/100 000 (–9.9%) between 2002 and 2012," the authors note. "All European countries, except Bulgaria, showed downward trends."

 

Inconsistencies of results 

Death rates from ovarian cancer fell by only 0.6% in Hungary between 2002 and 2012, compared with 28% in Estonia.
Other large declines seen in the United Kingdom, where ovarian cancer mortality fell by 22% between 2002 and 2012, Austria (18%) and in Denmark and Sweden (each at 24%).

Declines in ovarian cancer mortality in North America were actually larger than they were in the EU, the researchers note.


In the United States, mortality from ovarian cancer dropped by 16% over the same study interval. In 2012, mortality from ovarian cancer was less than 5% in both the United States and Canada.
In contrast, only moderate declines in ovarian cancer rates were seen in Japan and Hong Kong. No decline was seen in Korea, even though Korea has the lowest mortality rate from ovarian cancer among all of the countries considered, as Dr Vecchia pointed out.

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Of interest

 death rates from ovarian cancer traditionally been among the lowest in Japan, but now they are higher — at least in younger Japanese women — than in the EU or the United States, reflecting infrequent use of OCs in Japan, the authors comment.

Mortality from ovarian cancer declined by approximately 12% in both Australia and New Zealand, and by 2012 the rates in both countries were similar to those in North America.
However, the pattern of ovarian cancer mortality was "inconsistent" in Latin America, where some countries, such as Argentina, had a decline in ovarian cancer death rates, while other countries, including Brazil, Colombia, Cuba, Mexico, and Venezuela, all had increases in mortality rates.
On the other hand, "overall rates were systematically lower in Latin America...than in North America or Europe," the researchers observe.

Younger vs Older Women
Declines in death rates were also "systematically larger" in women aged 20 to 49 years, Dr Vecchia and coauthors add.
Rates of decline among women between 70 and 79 years of age in the EU were more modest, at approximately 2%, but again, there was significant variability between countries; rates dropped by about 31% in Denmark and by over 10% in the United Kingdom in the same age group.

Interestingly, the United States also had a large decline in death rates among older women, at about 18%.
Dr Vecchia and colleagues point out that the larger declines in ovarian cancer mortality rates seen in northern Europe and the United States among older women reflect the fact that OCs were introduced earlier there than in other countries and their use was more widespread.

Source: Malvezzi M, Carioli G, Negri E, et al. Global trends and predictions in ovarian cancer mortality. Annals of Oncology. 2016.

extracted from http://www.medscape.com/viewarticle/868512
  http://www.medscape.com/viewarticle/868512#vp_2