One-year survival from non-small cell lung cancer (NSCLC) – the most common form of the disease – ranged from 30 per cent in the UK to 46 per cent in Sweden. Survival was also relatively low in Denmark (34 per cent).
The research – carried out by the International Cancer Benchmarking Partnership (ICBP) – included more than 57,000 lung cancer patients diagnosed in 2004-07 and looked at the proportion of them who lived for longer than one year and at their stage at diagnosis.
The stage of a cancer indicates how big it is and how far it has spread.
UK survival figures were amongst the lowest at all stages compared to the other countries. This suggests lung cancer patients in the UK may not be getting the best available treatment, whatever the stage of their disease at diagnosis.
The proportion of patients diagnosed at an early stage of disease was slightly lower in the UK and Denmark than in the other four countries, suggesting that delayed diagnosis is playing a role.
In Denmark and the UK only one in seven patients with NSCLC were diagnosed at the earliest stage of disease (Stage 1**), compared with one in five in Sweden and Canada. One-year survival for patients with the earliest stage disease in the UK was 72.5 per cent, 16 per cent lower than in Sweden.
For small-cell lung cancer (SCLC), which is less common but more aggressive than NSCLC, the UK also had lower survival overall, and at each stage of diagnosis – except those patients where stage was unknown – than the other countries.
The comparisons used routinely collected population-based data. This allows a more accurate picture of lung cancer survival than is gathered from clinical trials. But international comparisons are complex because countries differ in how they collect information on stage at diagnosis, how fit the patients are and which diagnostic tests and treatments are available. All of these things could be contributing to the differences in lung cancer survival.
Dr Sarah Walters, lead author from the Cancer Research UK Cancer Survival Group at the London School of Hygiene and Tropical Medicine, said: “This is the first international population-based study of lung cancer survival by stage at diagnosis, and it includes nearly 60,000 patients. We’ve shown that wide international inequalities in lung cancer survival occur, even between patients who were diagnosed at the same stage of disease. This indicates that the quality of stage-specific treatment may differ even between these six wealthy countries with universal access to health care.
“It is clearly important to include stage at diagnosis in future international studies of cancer survival. Such comparisons would be easier if stage data were systematically recorded in the medical records, and coded in the cancer registries using international standard classifications.”
Sara Hiom, director of early diagnosis at Cancer Research UK, said: “This study and the ongoing work of the ICBP are hugely important. We’re learning more about the differences in cancer survival between countries and what might explain them. We need this information if we’re to help improve the outcome for cancer patients.
“This research should remind us that while great progress is being made in the diagnosis and treatment of cancer in the UK, we mustn’t be complacent. Around 35,000 people still die from lung cancer each year in the UK and that’s far too many. We would like to see ongoing improvements in data collection and the use of uniform systems for data on stage, in order to improve the accuracy of global comparisons.”
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* Walters, S et al. Lung cancer survival and stage at diagnosis in Australia, Canada, Denmark, Norway, Sweden and the United Kingdom: a population-based study, 2004-2007. Thorax 2013.
Notes to editors
Norway and Denmark contributed national data and regional data were used from the other countries, as follows: Australia: New South Wales; Canada: Alberta and Manitoba; Sweden: Uppsala-Örebro and Stockholm-Gotland health regions; United Kingdom: West Midlands Cancer Intelligence Unit (WMCIU), Eastern Cancer Registration and Information Centre (ECRIC) in England, and Northern Ireland.
** The stage of a cancer indicates how big it is and how far it has spread. The most widely used international system to classify cancer stage is called TNM. This indicates the size and position of the tumour (T), whether cancer cells have spread into the lymph nodes (N) and whether the tumour has spread anywhere else in the body – secondary cancer or metastases (M).
In order to produce the survival comparisons, the authors consolidated the stage data from the six countries because not all countries used the same classification system. They also had to predict the stage where it was missing.
About the International Cancer Benchmarking Partnership (ICBP):
The International Cancer Benchmarking Partnership (ICBP) is a unique and innovative global partnership of clinicians, academics and policymakers. The ICBP is funded by the UK Department of Health and Cancer Research UK. www.icbp.org.uk