Tuesday January 27 2015
Lung cancer has a relatively poor prognosis
The Mail Online states: “Lung cancer death rates among European women set to overtake breast cancer for first time this year,” adding that “researchers blame high levels of smoking, especially in Britain and Poland”.
The study used historical information on deaths from cancer (1970 to 2009) for the EU, to predict the number of deaths in 2015. It also did this for some individual countries, including the UK.
The overall results from the study were arguably positive. Cancer death rates for the EU have been declining in most cancers and are likely to continue declining in 2015. However, this masked less positive trends in specific cancer types, specific countries, and differences between men and women.
What hit the headlines was the prediction that lung cancer deaths in women will rise. The lung cancer death rate would be the highest of all cancer types for women, exceeding that of breast cancer for the first time.
The study didn’t investigate the reasons for the lung cancer mortality trend, but said that smoking was the likely culprit. Women who took up the habit in the past are likely to be now reaching the age where the cumulative effects of tobacco smoke will mean that approximately half of them will be killed by their habit.
Quitting smoking is likely to be the single biggest thing you can do to improve your health and many people don’t find it that difficult. Read our stop smoking advice.
Where did the story come from?
The study was carried out by researchers from universities based in Italy and Switzerland, and was funded by the Swiss League against Cancer, the Swiss Foundation for Research against Cancer, the Italian Association for Cancer Research and COST Action EU-Pancreas.
The study was published in the peer-reviewed medical journal Annals of Oncology. The study is free to view and download online.
The media coverage was generally balanced and included useful information on the potential explanations for the high rates of smoking in UK women.
The Mail Online quoted lead researcher Professor Carlo La Vecchia as saying, “This is due to the fact that British women started smoking during the Second World War, while in most other EU countries women started to smoke after 1968. It is worrying that female lung cancer rates are not decreasing in the UK, but this probably reflects the fact that there was an additional rise in smoking prevalence in the UK as well in the post-1968 generation – those born after 1950”.
What kind of research was this?
The research was an ecological study estimating the number of cancer cases across Europe for 2015, based on past trends.
The report’s authors wanted to update previous predictions for the EU made in 2012 and to explore prostate cancer, the third largest cause of male cancer deaths in the EU, in more depth.
An ecological study is good at estimating what happens at a wide geographic level to large groups of people. The drawback is that it cannot tell us what will happen to any one person. We could say that more women in the UK will probably die from lung cancer in 2015 than 2009, but we can’t say, based on this type of study, who will.
What did the research involve?
The researchers fed a statistical model with sets of historical data on stomach, colorectal, pancreas, lung, breast, uterus, prostate, cancers of the white blood cells, and total cancers from across the EU. The model estimated what cancer rates would be like in 2015, based on the previous trends.
Estimates of death rates by age group and gender were calculated for the EU as a whole, and individually for its most populous countries of France, Germany, Italy, Poland, Spain and the UK.
The data for the EU as a whole covered a period from 1970 to 2009. The UK-specific data was up-to-date as of 2010.
Data were obtained from the World Health Organization and Eurostat – both publically available sources of European statistics. These sources rely on official death certificate data, as well as population level estimates.
What were the basic results?
The overall picture was that cancer rates have been falling in the EU and in the UK since the 1970s, and that this trend is likely to continue overall. However, this masks a number of increasing trends for specific types of cancer, and differences between men and women.
Predicted overall cancer deaths in the EU for 2015
More than a million cancer deaths were predicted in the EU in 2015 (766,200 men and 592,900 women), corresponding to standardised death rates of 138.4 per 100,000 men and 83.9 per 100,000 women. Comparing 2009 data to 2015, total cancers are predicted to fall by 7.5% in men and 6% for women.
Pancreatic cancer had a negative outlook in both sexes, rising by 4% in men and 5% in women between 2009 and 2015.
Predicted female cancer deaths in the EU for 2015
In women, breast and colorectal cancers had favourable downward trends (-10% and -8%), but predicted lung cancer rates are set to rise 9% to 14.24 deaths per 100,000 women, becoming the cancer with the highest rate, reaching, and possibly overtaking, the breast cancer rate.
The total number of deaths predicted for 2015 remain higher for breast (90,800) than lung (87,500).
Predicted male cancer deaths in the EU for 2015
In men, predicted rates for the three major cancers in 2015 were lower than in 2009, with prostate falling by 12%, lung cancer by 9% and colorectal by 5%.
Prostate cancer showed estimated falls of 14%, 17% and 9% in the 35-64, 65-74 and over-75 age groups.
How did the researchers interpret the results?
The overall conclusions of the researchers were that: “Cancer mortality predictions for 2015 confirm the overall favourable cancer mortality trend in the EU, translating to an overall 26% fall in men since its peak in 1988, and 21% in women, and the avoidance of over 325,000 deaths in 2015, compared with the peak rate”.
This ecological study used historical information on deaths from cancer for the EU region (1970 to 2009) to predict the numbers of deaths in 2015.
The overall news was positive: cancer death rates for the EU have been declining in most cancers and are likely to continue declining in 2015. However, this masked other less positive trends in specific cancer types, specific countries, and differences between men and women.
The predictions that hit the headlines were that lung cancer deaths in women are going to rise. Moreover, that the rates (number of deaths per 100,000 women) would be the highest of all cancer types for women, knocking breast cancer off the top spot for the first time.
The study did not investigate the potential causes for the lung cancer death increases directly, but the likely culprit is smoking, which is one of the biggest risk factors for developing lung cancer. Women who took up the habit in the past are now reaching the age where the cumulative effects ensure that approximately half of them will be killed by their habit.
As with all ecological studies, these results cannot predict local variations in cancer rates or whether any specific individuals will get cancer. For example, there may be some areas in the UK where women’s lung cancer rates are actually declining, contrary to the EU or overall UK trend, whereas in others they may be increasing more rapidly than predicted. More focused data will help us when targeting public health resources to areas most in need.
Quitting smoking is likely to be the single biggest thing you can do to improve your health, and many people don’t find it that difficult. There are a number of proven aids to increase the chance of you beating the habit.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.