UICC World Cancer Congress 2006

It is a truism that for lung and other cancers, the first priority for developing countries is provision of basic services for diagnosis and treatment of the disease, coupled with efforts to combat the tobacco pandemic for primary prevention. Early detection tends to be a secondary goal, confined to medium-resource countries, and usually of a lower order of technology than in Western Europe or North America. Thus, for example, the trial of breast self-examination in China, and the studies of visual inspection with acetic acid for detection of cervical lesions in India.

Lung cancer has traditionally been characterised by poor survival both in the developing and the developed world (5-15% at 5 years). The major reason for this is the typically advanced stage at presentation. Only a small minority of cases are diagnosed at a stage amenable to surgical control. Where the tumour is respectable, however, survival is much improved, to 80% or more at 5 years. This would suggest that lung cancer may be susceptible to control by early detection, applied to long-term smokers or other high-risk groups. Although the previous trials of chest X-ray screening showed disappointing results, the more recent technology of spiral CT is promising. Results from the Early Lung Cancer Action Project show good program sensitivity and high rates of resectability and subsequent survival of screen-detected lung tumours. The technology is, however, suitable only for high-resource settings with the funds to afford it and the healthcare infrastructure to support it.

For lung cancer, it should be noted that although survival rates worldwide are poor, there is significant international variation, even within the developed countries. In the USA, France, Netherlands, Austria, Germany and Spain, 5-year survival rates for lung cancer in males are around 13%. In England, Wales and Scotland, they are around 7%, similar to those reported in Beijing. In European countries such as the Netherlands and France, there are no formal spiral CT screening programmes, yet these countries achieve considerably better survival rates than the UK. It is therefore likely that there are improvements which can be made, short of formal, high-technology screening, which can improve survival. In the UK, this idea has led to considerable interest in fast-track diagnosis and prompt delivery of the appropriate treatment.

Incidence and mortality from lung cancer are high in Western Europe, North America, Australasia and parts of East Asia, notably China. Lower rates are observed in many parts of Africa and the Middle East. Thus, if one is to look outside of the developed world for suitable areas for early detection of lung cancer, the appropriate environments are probably the rapidly developing areas of urban China rather than the very low-resource areas of Africa which spring to mind when one considers the developing world. While China can be considered to be developing in the sense that large numbers of its citizens live on relatively low incomes, it has the technological sophistication and the resources in some urban areas to develop early detection programmes. It also has a major public health problem of lung cancer, and therefore a substantial potential benefit from the intervention.

There are other implications of international variation in survival from lung and other cancers. In Nigeria, more than 80% of breast cancer is at stage 3 or worse at diagnosis, and median survival is around one year. That is, breast cancer in Nigeria has similar prognosis to lung cancer in the UK. In India, 5-year survival from breast cancer is around 60%, similar to the UK in the 1960's and 1970's. As healthcare develops in these countries, they have the opportunity to bypass some of the stages through which the developed countries have passed. For example, there is no need for a pre-tamixofen epoch in the developing countries. The treatment is already proven and it is cheap.

Can a similar argument apply to lung cancer? This is at least possible. Clearly, for countries with 3% five-year survival, the aim should be to catch up with best practice, which is achieving 13-17% five-year survival without formal early detection programmes, rather than with the 7% still prevalent in some of the developed world. This is likely to be achieved by prompt referral for diagnosis of those with symptoms and risk profiles characteristic of the disease, and by delivery of potentially curative treatment to all those diagnosed at a stage amenable to such therapy.

In terms of early detection, screening using high-technology imaging in the near future is likely to be an option only in the developed countries and in certain minority environments in the developing world. For both developed and developing countries, the future discovery of biological markers of presence of early disease or very high imminent risk would enable the selection of the small minority of subjects who would benefit most from the imaging screening. This would be of tremendous benefit worldwide in terms of both human and resource costs.