We’ve blogged before about the International Cancer Benchmarking Partnership (ICBP) – a collaboration between researchers trying to understand how and why cancer survival varies between different countries.
Earlier this month, they looked into differences in attitudes to, and awareness of, cancer and its symptoms (read more in this post).
And last year, they published work looking at differences in ovarian cancer survival rates, (which you can read about here).
As we explained at the time, this research showed that late diagnosis is unlikely to be the main reason for the poor UK ovarian cancer survival.
Instead, the ICBP found that UK women with advanced disease (i.e. that has spread) had worse chances of survival than those in other countries. Differences treatment in the UK may be contributing to this lower survival.
Today, the ICBP published a new paper looking at lung cancer survival. And again, it looks as though lack of treatment could be among the reasons behind the UK’s poor survival, but they also found evidence that late diagnosis is a contributing factor.
UK lung cancer patients also seem to be less likely to live for one year or longer after diagnosis than their counterparts in Australia, Norway, Canada and Denmark.
Let’s have a look at the details.
The new study examined international differences in survival for the two main types of lung cancer – the most common form, non-small cell lung cancer, and the less common type, small cell lung cancer.
Overall, the proportion of UK patients with either form of lung cancer who survived for a year or longer was lower than in other countries.
Digging a little deeper, they found that one-year survival for the non-small cell form ranged from 30 per cent in the UK to 46 per cent of patients in Sweden. Similarly the UK had the lowest one-year survival for small cell lung cancer – 25 per cent compared to 36 per cent in Sweden.
The researchers also worked out the proportion in each country who were diagnosed at each stage of the disease.
The proportion diagnosed at an early stage was slightly lower for non-small cell cancers in the UK and Denmark in comparison to the other countries.
Specifically, in the UK only one in seven patients with non-small-cell lung cancer was diagnosed at the earliest stage of the disease, compared with one in five in Sweden and Canada (countries with better lung cancer survival than the UK).
But there was also good news – the UK was among the best at diagnosing small-cell lung cancers at the earliest stages.
What does it mean?
Taken together, this suggests that late diagnosis is one reason why the UK’s lung cancer survival is lagging behind the best-performing countries, and suggests that diagnosing lung cancers at an earlier stage could help to improve the situation in the UK.
Thankfully, work is already in hand to try to diagnose lung cancers earlier.
For example, we’re working with the Department of Health (DH) to promote earlier diagnosis, and we’re co-chair the ‘National Awareness and Early Diagnosis Initiative’ (NAEDI).
This includes the DH-funded ‘Be Clear on Cancer’ campaigns, which encourage people to visit their GP sooner rather than later.
You can read the topline findings from the campaigns in the DH’s ‘Improving Outcomes; A Strategy for Cancer’ report.
Linking stage to survival
The new study also went on to look at how patients diagnosed at each stage of the disease fared subsequently – and how this differed between countries.
For non-small-cell disease, seven out of 10 UK patients with the earliest stage disease survived for at least a year, compared with about nine out of 10 people in Sweden (where survival at this stage was best).
Similarly, for small-cell lung cancer, around six out of 10 early stage patients survived for at least a year, compared with seven out of 10 in Sweden.
So even though we might be better than other countries at picking up small cell lung cancer at the earliest stages, UK patients still have a lower chance of surviving for at least a year.
Patients in the UK diagnosed at more advanced stages of both types of lung cancer also had among the worst one-year survival in the study.
Put simply, lung cancer patients in the UK are faring poorly compared to patients in other similar countries, irrespective of what stage the disease is picked up.
Why might this be?
There are a number of possibilities. We’ve discussed these in depth in the previous (ovarian cancer) post, but to recap:
- The standard of treatment could be lower here than it is elsewhere.
- There may problems with patients getting the best treatment, (For example, doctors may not be able to provide the best treatment options. We know that surgery for lung cancer is less frequently performed in the UK than in other countries).
- There may be some problems with the stage data.
And this latter point is important. Missing or inaccurate data, or differences in staging procedures, may make the comparisons between countries less accurate than the headline figures suggest . The study showed that the UK had the highest proportion of stage information missing (something we’ve discussed before). This means researchers weren’t able to find out how advanced many patients’ disease was at diagnosis.
The ICBP team developed a method that allowed them to estimate this (the technical term is ‘imputed’) – essentially using other data to try to work out the most likely stage at which a patient was diagnosed.
But having complete, routinely collected information about stage at diagnosis is extremely important, especially when trying to compare cancer survival internationally. This study, alongside the ICBP ovarian stage data, highlights the need for an improved and standardised stage data collection across the world to provide high-quality data for future comparative analyses.
Next up from the ICBP
As well as lung and ovarian cancers, the ICBP team has also been investigating survival differences in breast and bowel cancer.
We expect these results very soon – and we’ll be posting more analysis here on the blog.
- Sarah W. et al (2013). Lung cancer survival and stage at diagnosis in Australia, Canada, Denmark, Norway, Sweden and the UK: a population-based study, 2004–2007, Thorax, DOI: 10.1136/thoraxjnl-2012-202297