The occurrence of cancer looks set to double over the next 15+ years with researchers predicting a 75% rise in cancer incidence by 2030. In poorer countries, the number is closer to 90%.
The article published in the Lancet Oncology was prepared by Dr Freddie Bray of the International Agency for Research on Cancer (IARC) in Lyon, France. The aim of his work was to look at current and future patterns of incidence and mortality. They also looked at how different types of cancer vary between countries, using the Human Development Index to group and classify them.
It appears that cervical and stomach cancer are in decline in more developed countries, but those types of cancer are being superseded by breast, prostate and colorectal cancer that are more associated with the “western” lifestyle, of countries that are more socially and economically advanced.
Dr Bray goes on to say that
“Cancer is already the leading cause of death in many high-income countries and is set to become a major cause of morbidity and mortality in the next decades in every region of the world; this study serves as an important reference point in drawing attention to the need for global action to reduce the increasing burden of cancer.”
Using data from GLOBOCAN, a database compiled by the International Agency for Research on Cancer (IARC), Bray and colleagues looked at patterns of the most common types of cancer to see how they varied when compared to four levels of human development. They then used the information they gathered to predict how cancer incidence would change and countries become more developed.
In less developed countries, especially sub-Saharan Africa, cancer is more associated with infection and thus cervical and stomach cancer are more prevalent. In highly developed countries such as UK, Australia and Brazil the cancer burden is more aligned with lifestyle factors, reproductive risks, obesity and diet. Thus, we see female breast, prostate, and colorectal cancer being the most common.
In theory, if developing countries follow the same trends as those already enjoying a high level of economic prosperity, then the cancer trends will mirror the development. Thus countries such as China, South Africa and India will see cancer rates of these “lifestyle” cancers, rising rapidly. Researchers say as high as 93% by 2030.
In all the researchers predict the following trends:
- Prostate cancer and female breast cancer incidence rates appear to be rising in most countries currently with medium, high, or very high levels of HDI.
- Stomach cancer and cervical cancer are predominantly decreasing in countries with medium, high, or very high levels of HDI, although for cervix cancer, there are a number of exceptions.
- In countries with high and very high HDI levels, lung cancer incidence rates tend to be decreasing in men, but increasing in women, though in a given country this is dependent on the current stage of the tobacco epidemic; while lung cancer is not a leading cancer in low HDI regions at present, it will become a leading cause of cancer unless tobacco smoking is effectively controlled in these areas.
- In 2008, almost 40% of the incident cases of cancer that occur globally occur in very high HDI countries, despite these regions containing just 15% of the world’s population.
The authors highlight the fact that their data and work is fairly limited and their projections are constrained by these factors. Nonetheless, back of an envelope calculations can often prove to be highly accurate and efficient ways to make predictions, and if cancer rates rise amongst the more than 2 billion people in India and China, as they have done amongst the billion or so in the most developed countries, the rates of cancer will become quite shocking.
Dr Christopher Wild, IARC Director said:
“This study reveals the dynamic nature of cancer patterns in a given region of the world over time. Countries must take account of the specific challenges they will face and prioritize targeted interventions to combat the projected increases in cancer burden via effective primary prevention strategies, early detection, and effective treatment programs”.
Written by Rupert Shepherd