28 Nov Cancer Survival Varies Widely By Country and Cancer Type
MedicalResearch.com Interview with:
Dr Claudia Allemani PhD FHEA MFPH
Senior Lecturer in Cancer Epidemiology
Cancer Research UK Cancer Survival Group
Department of Non-Communicable Disease Epidemiology
London School of Hygiene and Tropical Medicine, London UK
Medical Research: What is the background for this study?
Dr. Allemani: Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control.
The first CONCORD study was published in 2008.1 It brought together data from 101 cancer registries in 31 countries, and included 1.9 million patients diagnosed during 1990-94 with a cancer of the colon, rectum, breast or prostate and followed up to the end of 1999. It revealed very wide international differences in five-year survival, and it confirmed the well-known racial discrepancy in cancer survival in the USA.
CONCORD-2 is the most comprehensive international comparison of trends in population-based cancer patient survival to date. It extends the first study in three ways:
- it covers 10 common cancers: collectively, these account for almost two-thirds (63%) of all cancer patients diagnosed each year in both developed and developing countries
- it includes data on more than 25 million cancer patients, provided by 279 cancer registries in 67 countries, in 40 of which the data provide complete (100%) coverage of the national population
- it examines trends in cancer survival for patients diagnosed over the 15-year period 1995-2009
Medical Research: What are the main findings?
Dr. Allemani: 5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005–09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide.
Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15–19% in North America, and as low as 7–9% in Mongolia and Thailand.
5-year survival for stomach cancer in 2005–09 was high (54–58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18–23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease.
Medical Research: What should clinicians and patients take away from your report?
Dr. Allemani: High survival from stomach cancer in Japan, Korea and Taiwan is well known, and is likely to be attributable to intensive diagnostic activity, early stage at diagnosis and radical surgery. Survival varies with sub-site and morphologic type, as well as stage. The types with better prognosis may also be more common in Japan and Korea, but the striking world-wide differences in survival suggest that important lessons could be learnt from these countries about early diagnosis and more effective treatment.
In striking contrast, survival from both adult and childhood leukaemia in several east Asian countries is surprisingly low. The low survival for adult leukaemia in Japan, South Korea, and Taiwan is especially surprising, because survival from stomach cancer and many other solid tumours is generally high. This raises the intriguing question of whether ethnic or genetic factors may be involved, as has recently been suggested by a comparison of chronic lymphocytic leukaemia survival between Taiwan and the USA. Leukaemia survival is also low in China, but haematological malignancies have received low priority in cancer control there, with limited access to health insurance and chemotherapy, and medical resources in rural areas are poor.
We believe that not only cancer patients, but the general public, in many countries around the world will be interested in the findings of this research programme. We know that cancer patient advocacy groups are very concerned when it is shown that survival is lower in their country than in nearby countries of comparable wealth and with similar healthcare systems. We expect the findings of this study to provide evidence for these groups to press for improvement in access to high-quality diagnosis and treatment and in the effectiveness of their healthcare systems.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Allemani: Cancer registries are crucial to our understanding of the global cancer burden. No other type of organisation can provide accurate population-based data on both the incidence of cancer and survival from cancer. Registries need to be adequately funded and equipped so that they can collect, analyse and publish accurate and complete incidence and survival data at national or regional level. Unfortunately, the situation of cancer registries in many countries is far from optimal. Many registries do not enjoy the appropriate level of political support to provide them with organisational stability, and they are often inadequately resourced: a number of registries that had expressed interest to participate in the CONCORD programme were unable to do so because they could not find the resources to complete the follow-up of all the registered patients to ascertain their vital status.
This is an absurd situation. If we assess the cost of registering a single cancer patient as the total budget of the cancer registry divided by the number of cases registered per year, then in most cases that cost is less than USD50 per case – less than the cost of a chest x-ray or a CT scan. Some of the newer chemotherapy regimes will cost USD100,000 per year per patient: their efficacy will have been proven in high-quality randomised trials, but many seem to offer only marginal improvement in disease-free or overall survival, typically in patients with more advanced disease. We need to question the logic of spending so little on cancer registration, which is the only information system that can tell us whether deployment of these expensive new regimes is effective at the population level.
The CONCORD programme at LSHTM represents the establishment of world-wide surveillance of cancer survival by centralised quality control and analysis of population-based registry data, as a comparative metric of the effectiveness of health systems. It will provide part of the evidence base for global policy on cancer control. It should contribute to the overarching goal of the World Cancer Declaration 2013.
To understand the reasons behind these wide world-wide differences in cancer survival, we plan the following lines of analysis, in collaboration with other members of the CONCORD Working Group:
- survival patterns by macro-economic indices (Gross Domestic Product, Total National Expenditure on Health) and other indices such as the Gini coefficient of inequality
- survival trends by anatomic sub-site, morphologic group and stage at diagnosis
- survival inequalities by race/ethnicity and socio-economic status
- avoidable premature deaths in populations with lower survival than other similar populations
- estimates of “cure” for selected cancers
We hope that the results of this study will stimulate clinicians, epidemiologists and public health analysts to explore the reasons for lower-than-expected levels of survival in their country or region. That would be the most powerful use of these data – a stimulus for more penetrating local research that could lead to earlier diagnosis, more prompt and equitable access to optimal treatment, and improved survival for cancer patients worldwide.
Global surveillance of cancer survival 1995–2009: analysis of individual data for 25 676 887 patients from 279 population-based registries in 67 countries (CONCORD-2)
Claudia Allemani PhD,Hannah K Weir PhD,Helena Carreira MPH,Rhea Harewood MSc,Devon Spika MSc,Xiao-Si Wang PhD,Finian Bannon PhD,Jane V Ahn MSc,Christopher J Johnson MPH,Audrey Bonaventure MD,Rafael Marcos-Gragera PhD,Charles Stiller MSc,Prof Gulnar Azevedo e Silva MD,Wan-Qing Chen PhD,Prof Olufemi J Ogunbiyi FWACP,Bernard Rachet FFPH,Matthew J Soeberg PhD,Hui You MAppStats,Tomohiro Matsuda PhD,Prof Magdalena Bielska-Lasota MD,Hans Storm MD,Prof Thomas C Tucker PhD,Prof Michel P Coleman FFPH,the CONCORD Working Group
The Lancet – 26 November 2014