For both colon and rectal cancer, survival among UK patients diagnosed at the earliest stage of disease (stage A) was similar to that in the other five countries (96%, compared to 92-98% elsewhere), but survival in the UK was consistently lower for those diagnosed at a more advanced stage (5-11% lower than elsewhere).
The researchers used population-based data for all patients diagnosed in a given country or region, not just the small proportion of patients included in clinical trials. The international differences in survival may arise from differences in the availability or use of diagnostic tests, and in the use of surgery, chemotherapy or radiotherapy at each stage of diagnosis. Countries do not all collect information on stage at diagnosis in the same way, however, and this can cause artefacts in international survival comparisons.
What are the survival rates for colorectal cancer by stage?
Survival rates are often used by doctors as a standard way of discussing a person’s prognosis (outlook). Some patients may want to know the survival statistics for people in similar situations, while others may not find the numbers helpful, or may even not want to know them. If you decide that you don’t want to know them, stop reading here and skip to the next section.
The 5-year survival rate refers to the percentage of patients who live at least 5 years after their cancer is diagnosed. Of course, many people live much longer than 5 years (and many are cured).
In order to get 5-year survival rates, doctors have to look at people who were treated at least 5 years ago. Improvements in treatment since then may result in a more favorable outlook for people now being diagnosed with colorectal cancer.
Survival rates are often based on previous outcomes of large numbers of people who had the disease, but they cannot predict what will happen in any particular person’s case. Knowing the type and the stage of a person’s cancer is important in estimating their outlook. But many other factors may also affect a person’s outlook, such as the grade of the cancer, the genetic changes in the cancer cells, and how well the cancer responds to treatment. Even when taking these other factors into account, survival rates are at best rough estimates. Your doctor can tell you if the numbers below may apply, as he or she is familiar with the aspects of your particular situation.
Camille Maringe, lead author based at the Cancer Research UK Cancer Survival Group at the London School of Hygiene & Tropical Medicine, said: “Accurate investigation of how far the cancer has spread (the stage) when it is diagnosed is essential for clinicians to be able to offer their patients the most appropriate treatment. This will increase survival. Investigation does not appear to be as thorough in the UK as in other countries, and except for patients with local tumours, survival is lower than in other countries at each stage of disease.
“We observed international differences in survival at each stage of disease. These differences are wider for older patients, and for patients whose disease is very advanced when they are diagnosed.
“Improvements are urgently needed in the quality and thoroughness of the medical tests that are used to assess the stage at diagnosis for each patient. The data collected by cancer registries on stage at diagnosis also need to be more accurate and complete. This will enable more accurate international comparisons of survival at each stage of disease. In turn, it will enable patients, doctors and healthcare planners to see which countries are setting the best standards, and what improvements are required to reach the highest levels of survival.”
Notes to editor:
1. Maringe et al. Stage at diagnosis and colorectal cancer survival in six high-income countries: A population-based study of patients diagnosed during 2000 – 2007 Acta Oncologica, 2013. DOI: 10.3109/0284186X.2013.764008
2. Data were from population-based registries in Australia (New South Wales); Canada ( Alberta and Manitoba (colon); Alberta, British Columbia and Manitoba (rectum); 2004-7 only); Denmark (national, 2004-7 only), Norway (national), Sweden (Uppsala-Örebro and Stockholm-Gotland health regions); UK (Northern Ireland, and all the regional cancer registries in England (colon); Northern Ireland, and all the regional cancer registries in England except the Thames Cancer Registry (rectum)).
3. The stage at diagnosis indicates how large the cancer is, and how far it has spread when diagnosed. One of the most widely used international system for classifying the stage of bowel cancer is called Dukes’ stage. This includes four stages (A-D), from tumours that are more or less localised (A, B), to those that have spread to the lymph nodes (C) or other parts of the body (D: secondary cancer or metastases).
About Cancer Research UK
Cancer Research UK is the world’s leading cancer charity dedicated to saving lives through research
The charity’s pioneering work into the prevention, diagnosis and treatment of cancer has helped save millions of lives.
Cancer Research UK receives no government funding for its life-saving research. Every step it makes towards beating cancer relies on every pound donated.
Cancer Research UK has been at the heart of the progress that has already seen survival rates in the UK double in the last forty years.
Cancer Research UK supports research into all aspects of cancer through the work of over 4,000 scientists, doctors and nurses.
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About the London School of Hygiene & Tropical Medicine
The London School of Hygiene & Tropical Medicine is a world-leading centre for research and postgraduate education in public and global health, with 3,500 students and more than 1,000 staff working in over 100 countries. The School is one of the highest-rated research institutions in the UK, and was recently cited as one of the world’s top universities for collaborative research. The School’s mission is to improve health and health equity in the UK and worldwide; working in partnership to achieve excellence in public and global health research, education and translation of knowledge into policy and practice.
London School of Hygiene & Tropical Medicine