WORLDWIDE CANCER INCIDENCE
Cancer has also fascinated the world’s academics and universities. In 1961, John F. Kennedy pledged to put a man on the moon by the end of the decade. Nine years later, Neil Armstrong and Buzz Aldrin walked on the moon. Ten years later, in 1971, Richard Nixon echoed this pledge by declaring a ‘war’ on cancer. Rather like the more recent ‘war on terror’, picking a fight with a multifaceted worldwide problem has been at best only partly successful. Nixon’s initial pledge was around $100 million, which seemed like a bonanza at the time, but has turned out to barely scratch the surface. Since 1971, billions more research dollars have followed, but more than 30 years later cancer remains one of the largest causes of death worldwide, with around 1 in 3 developing the disease in developed economies and 1 in 5 in the West dying from it. Curing cancer is clearly harder than ‘rocket science’.
Worldwide, huge amounts are spent on research into the causes and treatment of cancer. In 2009/10, the US National Cancer Institute spent $4.7 billion on cancer research; equivalent spend in Europe was around 1.4 billion. In the UK, the biggest spender is Cancer Research UK, one of the largest British charities, which in 2010 had an annual income from donations of more than £500 million, reflecting the importance attached to finding causes and cures for cancer among the wider population (the foremost recipients of public donations are, however, animals not people!). Despite this vast expenditure on research, we still do not really understand what causes a substantial proportion of cancers. Furthermore, despite the money spent on drugs and drug research, for the majority of patients cured of cancer, this is as a result of either surgery or radiotherapy. Chemotherapy and other newer treatments such as monoclonal antibodies or targeted ‘small molecule’ therapies, while growing in importance, still account for only a minority of cures but have a major role in palliation of advanced disease symptoms.
There are various ways of looking at the problem cancer poses. These range from the raw numbers – how many people diagnosed, how many people die – to the personal – what is your individual risk of getting particular cancer? Population-based statistics can be presented in various ways, from rates for the whole population to rates adjusted by age to calculations on numbers of years of life lost. These latter statistics are often expressed as years lost before the age of 70 – the biblical ‘three score years and ten’ – thereby assuming that deaths after 70 (or sometimes 75) essentially represent death from old age. A further complication is that deaths from cancer vary enormously by income, race, and country of residence. For example, breast and prostate cancers are much more common in Europe and North America than in Japan and China. Migrants from these countries to the United States progressively alter their risk of these cancers towards that of white Americans but retain a lower overall risk. This tells us that the lower rates of breast and prostate cancer in the Far East are partly down to environment and partly down to racial differences or some linked aspect of the environment that is portable – diet, for example.
To try and explore these concepts further, I will present samples of the raw statistics using a range of methods. The question of which statistic is most useful depends on your point of view. For example, doctors working in public health, responsible for planning healthcare provision for a local population, will not be very interested in the rates of an in another country. Conversely, researchers looking at the effect of diet on risk of cancer may well want to focus on differences in disease rates between societies, as they may shed light on which lifestyle factors are important in the development of a given cancer. Fundraisers for cancer research will tend to focus on diseases affecting large numbers in the target donating population – breast cancer is the best example of this in Europe and North America, but more recently fundraising for prostate cancer has tapped into the same vein of public opinion.