Breast cancer mortality has declined across Europe, but there are still notable differences between countries, according to new data presented at the 9th European Breast Cancer Conference in Glasgow, United Kingdom.
Researchers reported that the death rate from breast cancer had decreased in 31 European countries from 1989 to 2010. But the variations observed in individual countries cannot be explained simply by the resources devoted to cancer care.
The average annual change was –1.5% for all countries, and it appears that between 2003 and 2010, the average annual change was –1.9%. Decreases in breast cancer mortality have accelerated during the last decade, note the authors, and at present there is no sign that decreases will stabilize in coming years.
But while the decrease in breast cancer mortality in 2010 was greatest in countries with the highest death rates in the late 1980s, there were notable exceptions, said study author Philippe Autier, MD, PhD, from the Strathclyde Institute for Global Public Health at iPRI, Lyon, France.
The French Paradox
France, perhaps, represents the biggest conundrum.
"In 1987-9, rates in Italy, France and Norway were 29.7%, 28% and 27.4% respectively, but the respective declines in mortality rates 22 years later were 26.4%, 15.8%, and 34.5%, and of all European countries, the lowest mortality reductions in women aged less than 50 were also to be found in France," he said in a statement. "Given that France devotes substantial resources to cancer care and that Frenchwomen have access to the best treatment, there is something going on here that we don't understand and that needs urgent investigation."
In a 2010 paper published in the BMJ, Dr. Autier and colleagues had first noted the seeming "French paradox." (BMJ. 2010;341:c3620). At that time, the authors reported that "some countries, such as France and Sweden, have mobilized large resources on screening and acquisition of cancer drugs but have shown little change in breast cancer mortality."
At that time, the reaction of the French National Cancer Institute (INCA) was to say that the health benefits of the cancer plan were going to become apparent in the next few years, Dr. Autier said during a press briefing. "Four years later, positive changes announced by the INCA are still awaited."
France has a highly organized screening program and the highest spending on cancer drugs in Europe, and it is at the forefront of the use of new treatments. However, it has experienced a modest decrease in breast cancer mortality.
The same holds for Sweden, which has devoted considerable resources to screening yet has shown little change in mortality rates, Dr. Autier noted. There was a 23.7% decline in mortality between 1989 and 2010, but during that same time period, breast cancer mortality dropped by 34.3% in neighboring Norway—which introduced a nationwide screening program 15 years after Sweden did.
That said, considerable declines in breast cancer deaths have been observed in countries where major screening programs did not really get off the ground until after 2000 (Norway, Belgium, Switzerland, and Austria). These reductions were similar to or greater than those in countries that implemented screening at the end of the 1980s, such as Sweden, The Netherlands, the United Kingdom, and Finland.
"These are some of the many factors that continue to puzzle us, and we need to put considerable effort into finding out why these differences exist," Dr. Autier commented.
Screening Not Detecting Advanced Cancers
Another interesting observation was seen in the countries that formerly had the highest and lowest death rates.
In 1987–1989, breast cancer mortality rates were highest in England and Wales (41.9 per 100,000) and lowest in Romania (20 per 100,000). But in 2008–2010 these rates were 25.4 in England and Wales and 22 in Romania. This translates to a 40.8% decrease in mortality in England an 11.4% increase in Romania.
Many possible reasons may explain the differences observed between countries. Dr. Autier pointed to screening, which has played an important role in detecting tumors at smaller sizes. But trends in the incidence of advanced breast cancer have remained stable, suggesting that screening has not succeeded in detecting potentially life-threatening cancers at an earlier stage. In addition, the number of metastatic cancers present at diagnosis has also not declined.
"Hence these reductions in size simply represent the increasing incidence of small, early, non–life-threatening cancers that are detected by screening and which give an overall impression that things are getting better in terms of outcomes," said Dr. Autier. "As a result, we can say that decreased numbers of breast cancer deaths are largely due to improved treatments, not to screening."
Ongoing Challenge to Find Answers
Their report also showed that women under age 50 had the greatest reduction in mortality (from –71.3% to –21.4%). In contrast, the smallest decreases were observed in women 70 years and older (from –29.5% to 81.5%). Breast cancer mortality among older women is also continuing to rise in several countries, particularly those in central and Eastern Europe, a finding that can be attributed primarily to undertreatment.
"These findings are an important contribution to the ongoing challenge of understanding which strategies should be implemented to improve survival from breast cancer," said Hilary Dobson, MD, chair of 9th European Breast Cancer Conference's national organizing committee, clinical lead of the West of Scotland Breast Screening Service, and the lead clinician of the West of Scotland Cancer Advisory Network.
"Comparison among countries reveals a picture of variation and real complexity when considering factors such as population screening or access to cancer drugs," she said in a statement. "As no single factor emerges as an answer, continuing scrutiny on this scale and analysis is vital."
9th European Breast Cancer Conference. Presented March 28, 2014. Abstract O-410.
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